Low-density parity-check (ldpc) encoding method and apparatus

ABSTRACT

The present disclosure relates to low-density parity-check (LDPC) encoding methods and apparatus. One example method includes encoding k information bits by using a submatrix of ((n−k)/Z+j) rows and (n/Z+j) columns at an upper left corner of a check matrix H based on a first transmission code rate R satisfying R=k/(n+j×Z), obtaining a first codeword including the k information bits and (n−k+j×Z) redundant bits, and sending the first codeword to a receive end.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2020/125484, filed on Oct. 30, 2020, which claims priority toChinese Patent Application No. 201911047476.X, filed on Oct. 30, 2019.The disclosures of the aforementioned applications are herebyincorporated by reference in their entireties.

TECHNICAL FIELD

Embodiments of this application relate to the field of communicationstechnologies, and in particular, to a low-density parity-check (LDPC)encoding method and an apparatus.

BACKGROUND

To increase a throughput of a communications system, a hybrid automaticrepeat request (HARQ) technology is introduced into a next-generationwireless local area network (WLAN) in the new 802.1 lax. A principle ofHARQ is that: when decoding fails, a receive end stores received dataand requires a transmit end to retransmit data, and the receive endfirst combines the retransmitted data with the previously received dataand then performs decoding. In this way, a specific diversity gain isobtained, and a quantity of retransmissions is reduced, thereby reducinga latency. The HARQ technology mainly has two implementations: chasecombining (CC)-HARQ and incremental redundancy (IR)-HARQ.

The CC-HARQ technology combines a received error data packet with aretransmitted data packet for decoding, and this improves transmissionefficiency. In the IR-HARQ technology, the transmit end may sendinformation bits and initial redundant bits to a peer end during thefirst transmission. After receiving the information bits and the initialredundant bits, the receive end decodes the information bits based onthe initial redundant bits. If the decoding fails, the transmit endretransmits more redundant bits (which alternatively include some of theinformation bits) to the receive end, so as to reduce a channel codingrate. After receiving the retransmitted redundant bits (whichalternatively include some of the information bits), the receive endcombines the retransmitted redundant bits (which alternatively includesome of the information bits) with the initial bits, and decodes theinformation bits based on the combined bits. If the decoding fails, thetransmit end retransmits redundant bits (which alternatively includesome of the information bits) again. As a quantity of retransmissionsincreases, the redundant bits are continuously accumulated and acorresponding channel coding rate continuously decreases. Therefore,better decoding performance can be obtained.

It can be learned that, w % ben IR-HARQ is executed, new incrementalredundant bits need to be introduced during retransmission to reduce achannel coding rate. Currently, a rate-compatible (RC) LDPC code checkmatrix needs to be introduced, so as to introduce new incrementalredundant bits. However, an existing WLAN system supports only 12 LDPCcode check matrixes, and there are three code lengths: 648 bits, 1296bits, and 1944 bits. Each code length supports four different coderates: ½, ⅔, ¾, and ⅚. Each code length and each code rate jointlycorrespond to one different check matrix, that is, the LDPC code checkmatrix of each code length is not a rate-compatible check matrix, and isnot applicable to introducing new incremental redundant bits in IR-HARQ.

SUMMARY

Embodiments of this application provide an LDPC encoding method and anapparatus, so as to implement IR-HARQ transmission by using arate-compatible LDPC code check matrix.

To achieve the foregoing objective, the following technical solutionsare used in the embodiments of this application.

According to a first aspect, an LDPC encoding method is provided. Themethod includes: a transmit end obtains k information bits, performsLDPC encoding on the k information bits by using a first check matrixbased on a first transmission code rate R satisfying R=k/(n+j×Z), andsends an encoded first codeword including the k information bits and(n−k+j×Z) redundant bits to a receive end, where the first check matrixis a submatrix of the first ((n−k)/Z+j) rows and the first (n/Z+j)columns in a check matrix H, n is an integer greater than 0, j is aninteger greater than or equal to 0, and Z is an integer greater than 0;the check matrix H is a matrix of ((n−k)/Z+Q) rows and (n/Z+Q) columns,Q is an integer greater than or equal to j, each element in the checkmatrix H represents one Z×Z square submatrix, and the square submatrixis a cyclic permutation matrix of an identity matrix or an all-zeromatrix: the check matrix H includes a matrix H_(MC), a matrix H_(IR) ofQ rows and 24 columns, an all-zero matrix of 4 rows and Q columns, andan identity matrix of Q rows and Q columns: and the matrix H_(MC) is amatrix of (n−k)/Z rows and n/Z columns, the matrix H_(MC) is located atan upper left corner of the check matrix H, the matrix H_(IR) of Q rowsand 24 columns is located at a lower left corner of the check matrix H,the all-zero matrix of 4 rows and Q columns is located at an upper rightcorner of the check matrix H, and the identity matrix of Q rows and Qcolumns is located at a lower right corner of the check matrix H, thatis, the check matrix H is a matrix obtained by extending rows andcolumns of the matrix H_(MC).

It can be learned from the foregoing description that, the check matrixH of a minimum size may have at least (n−k)/Z rows and n/Z columns, thatis, the check matrix H of the minimum size may be the matrix H_(MC). Inthis case, the check matrix H can support a maximum transmission coderate of k/n. The check matrix H of a maximum size may have ((n−k)/Z+Q)rows and (n/Z+Q) columns. In this case, the check matrix H supports aminimum transmission code rate of k/(n+Q×Z). That is, as quantities ofrows and columns of the check matrix H change, the check matrix H cansupport a transmission code rate within a range of [k/(n+Q×Z), k/n] andhas a rate compatibility function. Therefore, according to the method inthe first aspect, the transmit end may perform, based on a transmissioncode rate required for sending the information bits, LDPC encoding onthe information bits by extracting check bits from a correspondingquantity of rows and a corresponding quantity of columns in therate-compatible check matrix H, so as to meet a transmission code raterequirement and improve data transmission reliability.

In a possible design, with reference to the first aspect, the methodfurther includes: when transmission of the first codeword fails, thetransmit end encodes the k information bits by using a second checkmatrix based on a second transmission code rate R satisfying R=k/(n+h×Z)to obtain a second codeword, where the second check matrix is asubmatrix of the first ((n−k)/Z+h) rows and the first (n/Z+h) columns inthe check matrix H, a code rate of the second check matrix is equal tothe second transmission code rate, and h is an integer greater than jand less than or equal to Q; and a code length of the second codeword is(n+h×Z), and the second codeword includes the k information bits and(n−k+h×Z) redundant bits; and the transmit end sends incrementalredundant bits to the receive end, or sends some of the k informationbits and incremental redundant bits to the receive end, where theincremental redundant bits are the (n−k+j×Z+1)^(th) to the(n−k+h×Z)^(th) redundant bits in the (n−k+h×Z) redundant bits, and h isan integer greater than j and less than or equal to Q.

Further, if the current retransmission fails, the transmit endretransmits new incremental redundant bits to the receive end again. Fora process of retransmitting incremental redundant bits each time, referto the possible design of the first aspect. Details are not describedagain.

According to the possible design, the transmit end may extract checkbits from corresponding rows and columns in the check matrix H based ona transmission code rate during retransmission, so that the extractedcheck bits meet a transmission code rate requirement, and the extractedcheck bits are used to encode the k information bits. Encoded newredundant bits or encoded new redundant bits and some of the encodedinformation bits are sent to the receive end. In this way, the transmitend retransmits the new incremental redundant bits to the receive end,thereby reducing a channel coding rate and improving decodingperformance.

In a possible design, with reference to any one of the first aspect orthe possible design of the first aspect, the matrix H_(IR) of Q rows and24 columns may include any Q rows in a 136-row matrix shown in Table 2in a specific implementation, for example, may be a matrix of the firstQ rows in Table 2, a matrix of the last Q rows in Table 2, a matrix of Qconsecutive rows starting from the q*^(h) row in Table 2, or a matrix ofnon-consecutive Q rows starting from the q^(th) row in Table 2, where qis an integer greater than or equal to 1.

In a possible design, with reference to any one of the first aspect orthe possible designs of the first aspect, the matrix H_(IR) of Q rowsand 24 columns may include any Q rows in a 100-row matrix shown in Table3 in a specific implementation, for example, may be a matrix of thefirst Q rows in Table 3, a matrix of the last Q rows in Table 3, amatrix of Q consecutive rows starting from the q^(th) row in Table 3, ora matrix of Q non-consecutive rows starting from the q^(th) row in Table3, where q is an integer greater than or equal to 1.

Based on the foregoing possible design, the matrix H_(IR) may beobtained from the preset multi-row matrix in Table 2 or Table 3, and theobtained matrix H_(IR) may be used to extend the matrix H_(MC) to obtainthe rate-compatible check matrix H.

In a possible design, with reference to any one of the first aspect orthe possible designs of the first aspect, the matrix H_(MC) is an LDPCcode check matrix with a code length n of 1944 and a code rate of ⅚ inan existing standard.

Based on the possible design, rows and columns of the LDPC code checkmatrix in the existing standard may be extended to obtain therate-compatible check matrix, that is, an existing encodingapparatus/decoding apparatus that performs encoding/decoding by usingthe check matrix with the code length n of 1944 and the code rate of ⅚may be reused, and a change to the hardware is relatively small.

According to a second aspect, this application provides a communicationsapparatus. The communications apparatus may be a transmit end, or a chipor a system on chip in the transmit end, or may be a function modulethat is in the transmit end and that is configured to implement themethod according to any one of the first aspect or the possible designsof the first aspect. The communications apparatus may implementfunctions performed by the transmit end in the foregoing aspect or thepossible designs, and the functions may be implemented by hardwareexecuting corresponding software. The hardware or software includes oneor more modules corresponding to the foregoing functions. For example,the communications apparatus may include a processing unit and a sendingunit.

The processing unit is configured to obtain k information bits andperform LDPC encoding on the k information bits by using a first checkmatrix based on a first transmission code rate R satisfying R=k/(n+j×Z),where the first check matrix is a submatrix of the first ((n−k)/Z+j)rows and the first (n/Z+j) columns in a check matrix H, n is an integergreater than 0, j is an integer greater than or equal to 0, and Z is aninteger greater than 0; the check matrix H is a matrix of ((n−k)/Z+Q)rows and (n/Z+Q) columns, Q is an integer greater than or equal to j,each element in the check matrix H represents one Z×Z square submatrix,and the square submatrix is a cyclic permutation matrix of an identitymatrix or an all-zero matrix; the check matrix H includes a matrixH_(MC), a matrix H_(IR) of Q rows and 24 columns, an all-zero matrix of4 rows and Q columns, and an identity matrix of Q rows and Q columns;and the matrix H_(MC) is a matrix of (n−k)/Z rows and n/Z columns, thematrix H_(MC) is located at an upper left corner of the check matrix H,the matrix H_(IR) of Q rows and 24 columns is located at a lower leftcorner of the check matrix H, the all-zero matrix of 4 rows and Qcolumns is located at an upper right corner of the check matrix H, andthe identity matrix of Q rows and Q columns is located at a lower rightcorner of the check matrix H, that is, the check matrix H is a matrixobtained by extending rows and columns of the matrix H_(MC).

The sending unit is configured to send an encoded first codewordincluding the k information bits and (n−k+j×Z) redundant bits to areceive end.

Specifically, for a specific execution process of each function modulein the second aspect, refer to the related descriptions in any one ofthe first aspect or the possible designs of the first aspect. Detailsare not described.

According to a third aspect, a communications apparatus is provided. Thecommunications apparatus may be a transmit end, or a chip or a system onchip in the transmit end. The communications apparatus may implementfunctions performed by the transmit end in the foregoing aspect or thepossible designs, and the functions may be implemented by hardware.

In a possible design, the communications apparatus may include aprocessor and a transceiver. The processor may be configured to supportthe communications apparatus in implementing the functions in any one ofthe first aspect or the possible designs of the first aspect. Forexample, the processor is configured to obtain k information bits, andperform LDPC encoding on the k information bits by using a first checkmatrix based on a first transmission code rate R satisfying R=k/(n+j×Z),where the first check matrix is a submatrix of the first ((n−k)/Z+j)rows and the first (n/Z+j) columns in a check matrix H, n is an integergreater than 0, j is an integer greater than or equal to 0, and Z is aninteger greater than 0; the check matrix H is a matrix of ((n−k)/Z+Q)rows and (n/Z+Q) columns, Q is an integer greater than or equal to j,each element in the check matrix H represents one Z×Z square submatrix,and the square submatrix is a cyclic permutation matrix of an identitymatrix or an all-zero matrix; the check matrix H includes a matrixH_(MC), a matrix H_(IR) of Q rows and 24 columns, an all-zero matrix of4 rows and Q columns, and an identity matrix of Q rows and Q columns;and the matrix H_(MC) is a matrix of (n−k)/Z rows and n/Z columns, thematrix H_(MC) is located at an upper left corner of the check matrix H,the matrix H_(IR) of Q rows and 24 columns is located at a lower leftcorner of the check matrix H, the all-zero matrix of 4 rows and Qcolumns is located at an upper right corner of the check matrix H, andthe identity matrix of Q rows and Q columns is located at a lower rightcorner of the check matrix H, that is, the check matrix H is a matrixobtained by extending rows and columns of the matrix H_(MC).

In another possible design, the communications apparatus may furtherinclude a memory. The memory is configured to store computer-executableinstructions that are necessary for the communications apparatus and thecheck matrix H. When the communications apparatus runs, the processorexecutes the computer-executable instructions stored in the memory, sothat the communications apparatus performs the LDPC encoding methodaccording to any one of the first aspect or the possible designs of thefirst aspect.

According to a fourth aspect, a computer-readable storage medium isprovided. The computer-readable storage medium may be a readablenon-volatile storage medium, and the computer-readable storage mediumstores instructions. When the instructions are run on a computer, thecomputer is enabled to perform the LDPC encoding method according to anyone of the first aspect or the possible designs of the foregoing aspect.

According to a fifth aspect, a computer program product includinginstructions is provided. When the instructions are run on a computer,the computer is enabled to perform the LDPC encoding method according toany one of the first aspect or the possible designs of the foregoingaspect.

According to a sixth aspect, a communications apparatus is provided. Thecommunications apparatus may be a transmit end, or a chip or a system onchip in the transmit end. The communications apparatus includes one ormore processors and one or more memories. The one or more memories arecoupled to the one or more processors. The one or more memories areconfigured to store computer program code. The computer program codeincludes computer instructions. When the one or more processors executethe computer instructions, the communications apparatus is enabled toperform the LDPC encoding method according to any one of the firstaspect or the possible designs of the first aspect.

For technical effects achieved in any design manner of the second aspectto the sixth aspect, refer to the technical effects achieved in any oneof the first aspect or the possible designs of the first aspect. Detailsare not described again.

According to a seventh aspect, an embodiment of this application furtherprovides a communications system. The communications system includes thecommunications apparatus and the receive end according to any one of thesecond aspect to the sixth aspect.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of an application scenario according to anembodiment of this application:

FIG. 2 is a schematic diagram of a communications apparatus according toan embodiment of this application;

FIG. 3 is a flowchart of an LDPC encoding method according to anembodiment of this application;

FIG. 4a shows a check matrix that supports a transmission code rate of5/7 according to an embodiment of this application;

FIG. 4b shows another check matrix that supports a transmission coderate of 5/7 according to an embodiment of this application:

FIG. 5 is a schematic diagram in which a transmit end sends a message toa receive end by using an IR-HARQ technology;

FIG. 6 is a schematic diagram in which a receive end decodes a messagesent by a transmit end;

FIG. 7 is a diagram of simulation curves according to an embodiment ofthis application;

FIG. 8 is a diagram of other simulation curves according to anembodiment of this application; and

FIG. 9 is a schematic diagram of composition of a communicationsapparatus according to an embodiment of this application.

DESCRIPTION OF EMBODIMENTS

The following describes the method provided in the embodiments of thisapplication with reference to the accompanying drawings.

The technical solutions in the embodiments of this application may beapplied to various mobile communications systems supporting IR-HARQ, forexample, a universal mobile telecommunications system (UMTS), aworldwide interoperability for microwave access (WiMAX) communicationssystem, a 4th generation (4G) system, a long term evolution (LTE)system, or a 5G (fifth generation, 5G) communications system, a newradio (NR) system, an NR-vehicle-to-everything (V2X) communicationssystem, or another next-generation communications system, and may alsobe applied to a wireless local area network (WLAN) supporting IR-HARQ,for example, may be applied to any of the Institute of Electrical andElectronics Engineers (IEEE) 802.11 series protocols currently used byWLANs, for example, applied to the 802.11 ay standard, or anext-generation standard of 802.11ay. In the embodiments of thisapplication, a WLAN communications system shown in FIG. 1 is used as anexample for description.

As shown in FIG. 1, the WLAN communications system may include one ormore basic service sets (BSSs). Network nodes in the basic service setinclude an access point (AP) and a station (STA). A transmit end and areceive end in embodiments of this application each may be an AP or aSTA in the WLAN system, or may be a chip located in an AP or a STA.Solutions in embodiments of this application may be applied tocommunication between an AP and a STA, or may be applied tocommunication between APs, or communication between STAs. Thecommunication may be one-to-one communication, or may be one-to-manycommunication or many-to-many communication. For example, thecommunication may be communication between one AP and one STA (forexample, as shown in the left diagram of FIG. 1), communication betweenone AP and a plurality of STAs (as shown in the right diagram of FIG.1), communication between a plurality of APs and a plurality of STAs, orcommunication between a plurality of APs and one STA.

The AP is a communications apparatus having a wireless transceiverfunction, and may be a directional multi-gigabit (DMG) AP, an enhanceddirectional multi-gigabit (EDMG) AP, or an AP supporting 60 GHz.However, this is not limited in embodiments of this application. The APmay also be referred to as a base station.

The STA may be a communications apparatus having a wireless transceiverfunction, for example, may be a wireless communications apparatussupporting 60 GHz communication. The STA may also be referred to as asubscriber unit, an access terminal, a mobile station, a remote station,a remote terminal, a mobile device, a user terminal, a terminal, awireless communications device, a user agent, a user apparatus, or userequipment (UE). Specifically, the STA may be terminal equipment, userequipment (UE), a mobile station (MS), a mobile terminal (MT), or thelike. Specifically, the STA may be a mobile phone, a tablet computer, ora computer with a wireless transceiver function, or may be a virtualreality (VR) terminal, an augmented reality (AR) terminal, a wirelessterminal in industrial control, a wireless terminal in self-driving, awireless terminal in telemedicine, a wireless terminal in a smart grid,a wireless terminal in a smart city, a smart home, a vehicle-mountedterminal, or the like.

In the WLAN system shown in FIG. 1, rows and columns of any check matrix(for example, a check matrix with a code length n of 1944 and a coderate of ⅚) in 12 LDPC code check matrixes specified in an existing WLANstandard may be extended to obtain a rate-compatible LDPC code checkmatrix. A transmit end and a receive end may prestore therate-compatible LDPC code check matrix. During initial transmission, thetransmit end may extract, based on a current transmission code rate, acorresponding submatrix from the rate-compatible LDPC code check matrixto perform LDPC encoding, so that encoded information bits meet thecurrent transmission code rate; and the transmit end may send theencoded information bits to the receive end. Correspondingly, thereceive end may extract, based on the current transmission code rate, acorresponding submatrix from the rate-compatible LDPC code check matrixto decode the encoded information bits sent by the transmit end. If thedecoding fails, during retransmission, the transmit end may extract,based on a transmission code rate in the retransmission, a correspondingsubmatrix from the rate-compatible LDPC code check matrix to performLDPC encoding, so that encoded information bits meet the transmissioncode rate in the retransmission, and the transmit end sends incrementalredundant bits to the receive end. Correspondingly, after receiving theincremental redundant bits, the receive end combines the receivedincremental redundant bits with a codeword obtained after the previousdecoding, for example, appends the received incremental redundant bitsto the codeword obtained after the previous decoding to form a newcodeword. In addition, the receive end extracts, based on thetransmission code rate in the retransmission, a corresponding submatrixfrom the rate-compatible LDPC code check matrix to decode the newcodeword. If the decoding succeeds, the process ends; otherwise,retransmission is performed again. In this way, the rate-compatible LDPCcode check matrix may be introduced into the WLAN communications systemto implement IR-HARQ transmission and improve transmission performance.Specifically, for the implementation process, refer to descriptions inthe embodiment corresponding to FIG. 3.

It should be noted that, in the embodiments of this application, thereceive end and the transmit end are relative concepts. The transmit endmay refer to a device that performs LDPC encoding on information bitsand sends the encoded information bits and/or incremental redundant bitsto a peer end. The receive end may refer to a device that receives theLDPC-encoded information bits and/or incremental redundancy bits, andthat decodes the received LDPC-encoded information bits. For example,the transmit end may be an AP 101 in the left diagram of FIG. 1, and thereceive end may be a STA 102 in the left diagram of FIG. 1.

In addition, FIG. 1 is an example framework diagram. A quantity of nodesincluded in FIG. 1 is not limited. In addition to the function nodesshown in FIG. 1, the WLAN communications system may further includeother nodes, such as a gateway device and an application server. This isnot limited. In the embodiments of this application, the transmit endand the receive end each may be a network node in the WLANcommunications system, or may be a chip in a network node in the WLANcommunications system.

A network element shown in FIG. 1, such as an AP or a STA, may use acomposition structure shown in FIG. 2 or include a component shown inFIG. 2. FIG. 2 is a schematic diagram of composition of a communicationsapparatus 200 according to an embodiment of this application. Thecommunications apparatus 200 may be an AP, or a chip or asystem-on-a-chip in an AP. As shown in FIG. 2, the communicationsapparatus 200 may include a processor 201, a communications line 202,and a transceiver circuit 203. Further, the communications apparatus 200may include a memory 204. The processor 201, the memory 204, and thetransceiver circuit 203 may be connected to each other through thecommunications line 202.

The processor 201 may be a central processing unit (CPU), ageneral-purpose processor, a network processor (NP), a digital signalprocessor (digital signal processing, DSP), a microprocessor, amicrocontroller, a programmable logic device (PLD), or any combinationthereof. The processor 201 may alternatively be another apparatus havinga processing function, for example, a circuit, a component, or asoftware module. The processor 201 may have functions such as encoding,modulation, demodulation, decoding, and the like.

The communications line 202 is used to transmit information betweencomponents included in the communications apparatus 200.

The transceiver circuit 203 is configured to communicate with anotherdevice or another communications network. The another communicationsnetwork may be the Ethernet, a radio access network (RAN), a wirelesslocal area network (WLAN), or the like. The transceiver circuit 203 maybe a radio frequency module or any apparatus that can implementcommunication. In this embodiment of this application, only an examplein which the transceiver circuit 203 is a radio frequency module is usedfor description. The radio frequency module may include an antenna, aradio frequency circuit, and the like. The radio frequency circuit mayinclude a radio frequency integrated chip, a power amplifier, and thelike.

The memory 204 is configured to store instructions and a rate-compatibleLDPC code check matrix. The instruction may be a computer program. Therate-compatible LDPC code check matrix may be a check matrix obtainedafter rows and columns of an LDPC code check matrix in an existing WLANstandard are extended, for example, may be the following check matrix Hof ((n−k)/Z+Q) rows and (n/Z+Q) columns.

The memory 204 may be a read-only memory (ROM) or another type of staticstorage device that can store static information and/or instructions, ormay be a random access memory (RAM) or another type of dynamic storagedevice that can store information and/or instructions, or may be anelectrically erasable programmable read-only memory (EEPROM), a compactdisc read-only memory (CD-ROM) or another optical disk storage, anoptical disc storage, a magnetic disk storage medium, or anothermagnetic storage device. The optical disc storage includes a compactdisc, a laser disc, an optical disc, a digital versatile disc, a Blu-raydisc, and the like.

It should be noted that the memory 204 may exist independently of theprocessor 201, or may be integrated with the processor 201. The memory204 may be configured to store instructions, program code, some data, orthe like. The memory 204 may be located inside the communicationsapparatus 200, or may be located outside the communications apparatus200. This is not limited. The processor 201 is configured to execute theinstructions stored in the memory 204, to implement an LDPC encodingmethod provided in the following embodiments of this application.

In an example, the processor 201 may include one or more CPUs, forexample, a CPU 0 and a CPU 1 in FIG. 2.

In an optional implementation, the communications apparatus 200 includesa plurality of processors. For example, in addition to the processor 201in FIG. 2, the communications apparatus 200 may further include aprocessor 207.

In an optional implementation, the communications apparatus 200 furtherincludes an output device 205 and an input device 206. For example, theinput device 206 is a device, for example, a keyboard, a mouse, amicrophone, or a joystick, and the output device 205 is a device, forexample, a display screen or a speaker.

It should be noted that the communications apparatus 200 may be adesktop computer, a portable computer, a network server, a mobile phone,a tablet computer, a wireless AP, an embedded device, a chip system, ora device with a structure similar to that in FIG. 2. In addition, thecomposition structure shown in FIG. 2 does not constitute a limitationon the communications apparatus. In addition to the components shown inFIG. 2, the communications apparatus may include more or fewercomponents than those shown in the figure, or have different componentarrangements, or some components are combined.

In embodiments of this application, the chip system may include a chip,or may include a chip and another discrete component.

The following describes an LDPC encoding method provided in anembodiment of this application with reference to the WLAN communicationssystem shown in FIG. 1. Each device in the following embodiments mayhave the components shown in FIG. 2. For actions, terms, and the likeused in embodiments of this application, reference may be made to eachother. In embodiments of this application, a name of a message exchangedbetween devices, a name of a parameter in the message, or the like ismerely an example. During specific implementation, another name mayalternatively be used. This is not limited.

FIG. 3 shows an LDPC encoding method according to an embodiment of thisapplication. As shown in FIG. 3, the method may include the followingsteps.

Step 301: A transmit end obtains k information bits.

The transmit end may be an AP 101 or a STA 102 in FIG. 1. This is notlimited.

k is an integer greater than 0. For example, a value of k may be81×20=1620 in this embodiment of this application.

The k information bits may all be valid payload bits or validinformation bits. Alternatively, some bits may be valid payload bits orvalid information bits, and remaining bits may be padding bits orshortened all-zero padding bits. The valid payload bits and theremaining bits together form the k to-be-encoded information bits. Forexample, the k information bits may include (k−s) valid information bitsand s shortened all-zero padding bits.

For example, a baseband module in the transmit end may generate validinformation bits. A length of the valid information bits may be lessthan or equal to k. The transmit end may obtain the k information bitsbased on the valid information bits generated by the baseband module.For example, if a quantity of the valid information bits is k. LDPCencoding is directly performed on the valid information bits generatedby the baseband module; or if the quantity of the valid information bitsgenerated by the baseband module is less than k, all-zero padding isperformed on the valid information bits to obtain the k informationbits.

Step 302: The transmit end performs LDPC encoding on the k informationbits by using a first check matrix based on a first transmission coderate R satisfying R=k/(n+j×Z).

The first transmission code rate may be a rate at which the transmit endtransmits information to a receive end this time. The first transmissioncode rate may be any one of transmission code rates predefined in a WLANstandard. Specifically, the transmit end may select, based on acommunications environment between the transmit end and the receive endand another parameter, one code rate from the transmission code ratespredefined in the WLAN standard as the first transmission code rate. Thetransmission code rates predefined in the WLAN standard may include ½,⅔, ¾, ⅚, 5/7, ⅞, and the like.

The first check matrix is a submatrix of the first ((n−k)/Z+j) rows andthe first (n/Z+j) columns in a check matrix H, and a code rate of thefirst check matrix is equal to the first transmission code rate. Itshould be noted that, that the transmit end performs LDPC encoding onthe k information bits by using a first check matrix may specificallybe: the transmit end expands each element in the first check matrixbased on a Z×Z square submatrix, and the transmit end performs LDPCencoding on the k information bits based on a parity check matrix of((n−k)+j×Z) rows and (n+j×Z) columns that is obtained by expansion. Forexample, the transmit end may perform LDPC encoding on the k informationbits by using the parity check matrix of (n−k)+j×Z) rows and (n+j×Z)columns by referring to a conventional technology. Details are notdescribed.

n is an integer greater than 0, for example, n may be 1944; j is aninteger greater than or equal to 0; and Z is an integer greater than 0,for example, Z may be 81. It should be noted that, the firsttransmission code rate R is not limited to ⅚, and may alternatively be5/7, ⅔, or the like. For example, Z=81. When k=1620, n=1944, and j=0,R=⅚. When k=1620, n=1944, and j=4. R= 5/7.

The check matrix H may be a matrix obtained by extending an LDPC codecheck matrix of ((n−k)/Z) rows and (n/Z) columns in an existing WLANstandard by Q rows and Q columns. For example, the check matrix H may bea matrix of ((n−k)/Z+Q) rows and (n/Z+Q) columns. Q is an integergreater than or equal to j, for example, Q may be 100. The check matrixsupports a minimum transmission code rate of k/(n+Q×Z), and a maximumtransmission code rate of k/n. When Q=100, n=1944, k=1620, and Z=81, theminimum transmission code rate of the check matrix H is 0.161, and themaximum transmission code rate supported by the check matrix H is ⅚. Inactual application, to implement any transmission code rate within arange of [0.161, ⅚], a submatrix at an upper left corner of the checkmatrix H may be extracted, so that the extracted submatrix supports thetransmission code rate that needs to be implemented.

For example, the check matrix H may be a mother matrix or a base matrixof a parity check matrix of (n−k+Q×Z) rows and (n+Q×Z) columns. Eachelement in the check matrix H represents one Z×Z square submatrix. Thesquare submatrix is a cyclic permutation matrix of an identity matrix oran all-zero matrix. The all-zero matrix may also be described as a zerosubmatrix with all-zero entries. That is, the parity check matrix of(n−k+Q×Z) rows and (n+Q×Z) columns may be divided into squaresubmatrixes whose size is Z×Z to obtain the check matrix H, or Z×Zsubmatrixes corresponding to all elements in the check matrix H may beexpanded to obtain the parity check matrix of (n−k+Q×Z) rows and (n+Q×Z)columns.

In this embodiment of this application, the identity matrix may bedenoted as P0. A matrix obtained by cyclically permutating the identitymatrix P0 rightward by i elements is referred to as a cyclic permutationmatrix (CPM). A subscript i of the cyclic permutation matrix CPMindicates a quantity of bits by which the identity matrix is cyclicallypermutated rightward. For example, P0 may be shown by matrix (1):

$\begin{matrix}\begin{bmatrix}1 & 0 & \ldots & 0 & 0 \\0 & 1 & \ldots & 0 & 0 \\ \vdots & \vdots & \ddots & \vdots & \vdots \\0 & 0 & \ldots & 1 & 0 \\0 & 0 & \ldots & 0 & 1\end{bmatrix} & {{matrix}(1)}\end{matrix}$

The identity matrix P0 may be cyclically permutated rightward by oneelement to obtain a cyclic permutation matrix P1. P1 is shown by matrix(2). Similarly, the identity matrix may be cyclically permutatedrightward by 2 elements to obtain a cyclic permutation matrix P2, andcyclically permutated rightward by 3 elements to obtain a cyclicpermutation matrix P3, . . . , until the identity matrix is cyclicallypermutated rightward by 80 elements to obtain a cyclic permutationmatrix P80.

$\begin{matrix}\begin{bmatrix}0 & 1 & 0 & \ldots & 0 \\0 & 0 & 1 & \ldots & 0 \\ \vdots & \vdots & \vdots & \ddots & \vdots \\0 & 0 & 0 & \ldots & 0 \\1 & 0 & 0 & \ldots & 0\end{bmatrix} & {{matrix}(2)}\end{matrix}$

In this embodiment of this application, the check matrix H may bespecified in the IEEE 802.11ac/ax standard, and prestored at thetransmit end. The check matrix may include a matrix H_(MC), a matrixH_(IR) of Q rows and 24 columns, an all-zero matrix of 4 rows and Qcolumns, and an identity matrix of Q rows and Q columns; and the matrixH_(MC) is a check matrix of (n−k)/Z rows and n/Z columns, the matrixH_(MC) is located at the upper left corner of the check matrix H, thematrix H_(IR) of Q rows and 24 columns is located at a lower left cornerof the check matrix H, the all-zero matrix of 4 rows and Q columns islocated at an upper right corner of the check matrix H, and the identitymatrix of Q rows and Q columns is located at a lower right corner of thecheck matrix H, that is, the check matrix H may be considered as amatrix obtained by extending rows and columns of the matrix H_(MC).Extracting elements in the first ((n−k)/Z+j) rows and the first (n/Z+j)columns of the check matrix H may be: extracting a submatrix from thefirst row to the ((n−k)/Z+j)^(th) row and from the first column to the(n/Z+j)^(th) column in the check matrix H. Z×Z square submatrixescorresponding to all elements in the first check matrix of (n−k)/Z+j)rows and (n/Z+j) columns may be expanded to obtain a parity check matrixof (n−k+j×Z) rows and (n+j×Z) columns.

For example, Q=100, (n−k)/Z=4, and n/Z=24. The check matrix may be shownby matrix (3). If the first transmission code rate is ⅚, n=1944, andZ=81, the submatrix H_(MC) from the first row to the fourth row and fromthe first column to the 24^(th) column in matrix (3) is extracted as thefirst check matrix.

$\begin{matrix}{H = \begin{bmatrix}H_{MC} & 0_{4 \times 100} \\H_{IR} & I_{100 \times 100}\end{bmatrix}} & {{matrix}(3)}\end{matrix}$

In this embodiment of this application, the matrix H_(MC) may be any oneof 12 LDPC code check matrixes adopted in the existing Institute ofElectrical and Electronics Engineers (IEEE) 802.11ac/802.1 lax standard.The 12 LDPC code check matrixes include code lengths of 648, 1296, and1944. Each code length supports check matrixes with four different coderates: ½, ⅔, ¾, and ⅚. For example, an example in which the matrixH_(MC) is a check matrix with the code length of 1944 and the code rateof ⅚ shown in Table 1 is used for description in this embodiment of thisapplication. For a process in which another existing check matrix isused as the matrix H_(MC), and rows and columns of the another existingcheck matrix are extended to obtain the check matrix H, refer to themethod described in this embodiment of this application. Details are notdescribed again.

TABLE 1 10 40 67 55 3 62 5 25 64 43 31 50 41 61 26 62 61 19 0 0 58 53 6247 54 64 48 54 5 13 43 54 57 7 40 52 45 22 0 0 43 12 0 67 20 21 35 45 3759 59 7 56 29 48 24 44 0 0 0 13 24 30 34 37 47 49 31 42 20 54 3 54 43 361 43 0 0

The matrix H_(IR) of Q rows and 24 columns may be obtained from a matrixshown in Table 2 or Table 3 below.

In an example, the matrix H_(IR) of Q rows and 24 columns is any Q-rowmatrix in the 136-row matrix shown in Table 2 below. Each row in thepreset 136-row matrix includes 24 elements, each element represents onesquare submatrix whose size is Z×Z, a null element in each rowrepresents an all-zero matrix, and a specific value of a non-nullelement in each row is a cyclic permutation value of an identity matrix.It should be noted that, if each entry in the 136-row matrix shown inTable 2 is expanded into a Z×Z square submatrix, the 136-row matrixshown in Table 2 may further be replaced by a parity check matrix of136×Z rows and 24×Z columns.

The matrix H_(IR) of Q rows and 24 columns is any Q-row matrix in the136-row matrix shown in Table 2 below, and this may indicate that thematrix H_(IR) of Q rows and 24 columns is a matrix of the first Q rows,a matrix of the last Q rows, a matrix of Q consecutive rows startingfrom the q^(th) row, or a matrix of Q non-consecutive rows starting fromthe q^(th) row in the 136-row matrix below, where q is an integergreater than or equal to 1.

TABLE 2 25 24 6 47 73 23 16 49 30 16 47 19 65 40 44 0 60 71 56 53 55 2455 39 79 68 14 43 71 18 8 25 18 16 73 35 17 53 30 13 57 47 52 5 78 13 3177 13 10 53 23 66 48 71 11 4 66 10 9 10 37 18 52 68 2 43 75 73 12 55 2933 49 0 69 62 55 33 4 51 39 24 33 7 42 80 31 60 52 44 69 41 19 37 10 6128 9 27 49 61 54 30 69 56 18 24 68 39 34 49 47 40 35 43 72 27 45 52 3455 9 33 58 68 77 38 52 51 45 40 40 20 19 71 4 9 62 26 26 61 45 60 21 663 53 79 4 74 19 57 40 16 28 65 37 43 40 52 51 78 79 60 11 40 52 79 4670 51 70 80 20 42 58 6 4 14 31 80 5 20 68 37 32 75 28 74 42 16 75 80 6335 52 14 62 8 29 45 26 57 56 24 40 33 51 17 32 80 2 49 78 12 24 55 34 804 36 24 64 20 56 38 77 50 47 21 34 65 69 17 44 59 63 10 55 58 68 30 69 711 59 25 76 8 39 11 49 67 39 26 57 73 24 45 42 1 60 73 73 56 77 10 3 3961 44 70 68 7 43 78 20 55 76 3 37 59 7 38 70 64 41 63 31 63 2 5 60 78 5710 67 17 17 0 46 59 51 7 33 22 27 4 19 9 6 0 43 38 64 5 63 73 55 7 44 1221 31 28 57 2 28 32 65 45 2 41 53 60 62 67 65 56 17 14 53 1 20 31 34 210 65 63 32 14 39 11 58 18 75 43 74 25 75 0 65 6 80 67 16 58 76 2 76 2 7070 19 5 26 61 46 16 70 20 73 21 66 29 50 7 50 78 7 51 16 75 69 61 77 3536 4 41 73 14 17 20 4 17 76 23 68 8 6 52 70 55 37 50 44 6 54 16 55 14 5163 70 65 13 25 64 4 74 80 79 45 48 58 34 25 34 52 30 10 16 36 30 65 5441 73 53 8 51 56 30 5 43 69 55 42 14 7 74 47 63 21 74 20 11 8 38 60 7573 40 29 14 44 73 41 9 62 24 25 9 39 6 33 17 66 68 72 74 58 44 68 1 7671 1 70 44 13 74 16 48 50 51 56 53 72 12 70 80 1 4 36 30 44 27 42 50 4579 64 62 79 59 76 42 71 17 14 58 31 44 21 56 10 74 54 8

In another example, the matrix H_(IQ) of Q rows and 24 columns is anyQ-row matrix in the 100-row matrix shown in Table 3 below. Each row inthe preset 100-row matrix includes 24 elements, each element representsone square submatrix whose size is Z×Z, a null element in each rowrepresents an all-zero matrix, and a specific value of a non-nullelement in each row is a cyclic permutation value of an identity matrix.It should be noted that, if each element shown in Table 3 is expandedinto a Z×Z square submatrix, the 100-row matrix shown in Table 3 mayfurther be replaced by a parity check matrix of 100-Z rows and 24×Zcolumns.

The matrix H_(IR) of Q rows and 24 columns is any Q-row matrix in the100-row matrix shown in Table 2 below, and this may indicate that thematrix H_(IR) of Q rows and 24 columns is a matrix of the first Q rows,a matrix of the last Q rows, a matrix of Q consecutive rows startingfrom the q^(th) row, or a matrix of Q non-consecutive rows starting fromthe q^(t)a row in the 100-row matrix below, where q is an integergreater than or equal to 1.

TABLE 3 60 15 34 80 20 29 39 22 77 7 7 72 79 69 49 75 8 2 56 22 58 18 4721 80 38 50 75 32 21 26 30 36 44 67 63 2 55 18 63 78 44 67 14 35 73 9 565 9 45 67 50 25 8 53 45 28 50 62 34 8 4 76 80 50 13 40 32 0 20 47 38 5545 67 71 57 38 47 79 7 76 27 33 49 58 19 26 31 39 68 17 6 76 24 69 3 4340 34 37 42 1 10 59 47 66 63 74 26 47 3 53 67 67 46 69 56 35 36 54 17 726 77 24 43 32 36 9 76 3 78 14 45 0 59 39 4 4 54 31 31 48 39 33 32 34 4647 6 69 22 66 64 10 77 42 23 62 65 43 43 6 48 16 29 23 3 11 44 34 70 5949 16 1 77 19 8 10 17 44 20 18 17 17 71 16 4 69 27 18 36 0 52 43 42 3956 31 14 50 9 22 38 64 80 43 80 59 34 48 31 22 77 71 21 54 41 65 58 7847 56 70 21 13 8 41 22 19 63 74 59 58 17 14 59 72 32 29 29 71 79 21 2446 46 19 51 53 75 34 28 79 24 34 64 73 25 49 48 18 64 72 41 41 1 32 7445 9 50 25 72 18 75 11 40 34 43 57 71 76 29 74 67 54 5 23 66 70 41 17 5972 74 3 25 31 54 65 68 15 18 29 11 21 33 30 29 80 50 41 79 51 41 45 1877 3 51 6 34 58 67 14 30 56 69 64 58 59 11 74 48 38 41 52 16 58 63 80 82 25 64 35 68 4 26 39 66 61 26 50 31 11 18 73 80 44 54 28 68 0 55 53 342 65 72 73 54 11 69 44 15 70 57 48 61 48 30 72 80 47 4 23 72 59 4 69 6622 52 53 60 35 13 65 44 68 16 9 9 10 3 7 50 5 62 20 80

It should be noted that, Table 2 and Table 3 are merely example tables.In addition to the expression manners shown in Table 2 and Table 3, thepreset 136-row matrix or the preset 100-row matrix may alternatively beexpressed in another form, for example, an array. The preset 100-rowmatrix is used as an example. The 100-row matrix shown in Table 3 mayalso be presented in a manner shown in Table 4 below.

Table 4 includes 101 rows. The first row is a header, and the remaining100 rows are the preset 100-row matrix. The header includes dc andvalues 1 to 11. dc represents a quantity of non-null elements, and acolumn corresponding to dc represents a quantity of non-null elements ineach row. A column corresponding to the i^(th) value in the values 1 to11 represents a feature of the i^(th) non-null element in each row. InTable 4, a feature of a non-null element is represented by (a firstvalue, a second value). The first value indicates a value obtained bysubtracting 1 from a column index of the non-null element in the checkmatrix H, and the second value indicates a value of the non-null elementor a cyclic permutation value of a cyclic permutation matrixcorresponding to the non-null element. For example, dc corresponding tothe first row in the 100-row matrix is 11, and this indicates that thefirst row includes 11 non-null elements. (0, 60) in Table 4 indicatesthat a non-null element exists in the first row and the first column ofthe 100-row matrix, and a value of the non-null element is 60.

TABLE 4 dc 1 2 3 4 5 6 7 8 9 10 11 11 0.60 1.15 3.34 4.80 5.20 6.29 7.399.22 11.77 12.7 18.7 10 0.72 2.79 3.69 4.49 5.75 6.8 9.2 11.56 12.2214.58 8 1.18 2.47 4.21 5.80 6.38 7.50 9.75 11.32 9 0.21 1.26 2.30 3.364.44 5.67 6.63 7.2 11.55 9 0.18 2.63 3.78 4.44 6.67 8.14 9.35 11.73 14.99 1.56 2.5 3.9 5.45 6.67 7.50 9.25 17.8 19.53 8 0.45 1.28 3.50 4.62 6.347.8 9.4 20.76 7 2.80 3.50 4.13 5.40 6.32 9.0 10.20 8 1.47 2.38 3.55 4.456.67 7.71 9.57 23.38 7 1.47 2.79 3.7 4.76 6.27 9.33 21.49 7 1.58 2.193.26 4.31 5.39 9.68 15.17 6 2.6 3.76 5.24 6.69 7.3 16.43 6 1.40 3.346.37 7.42 9.1 13.10 6 1.59 2.47 3.66 6.63 9.74 17.26 6 2.47 3.3 4.535.67 7.67 22.46 6 3.69 4.56 5.35 6.36 9.54 18.17 6 3.7 6.26 7.77 9.2416.43 22.32 5 1.36 2.9 3.76 6.3 8.78 5 1.14 2.45 6.0 7.59 19.39 5 1.43.4 6.54 8.31 13.31 5 1.48 2.39 3.33 6.32 10.34 5 1.46 4.47 6.6 13.6920.22 5 1.66 3.64 6.10 9.77 23.42 5 1.23 2.62 6.65 15.43 16.43 5 1.62.48 3.16 6.29 12.23 5 2.3 3.11 6.44 8.34 16.70 4 1.59 2.49 3.16 14.1 52.77 3.19 6.8 13.10 21.17 5 1.44 2.20 3.18 14.17 19.17 4 3.71 6.16 9.410.69 4 2.27 3.18 12.36 14.0 5 1.52 3.43 6.42 8.39 20.56 4 1.31 6.148.50 22.9 4 3.22 6.38 9.64 18.80 4 1.43 2.80 3.59 17.34 5 2.48 3.31 6.2215.77 16.71 4 3.21 6.54 10.41 13.65 4 3.58 6.78 14.47 18.56 5 1.70 3.216.13 11.8 13.41 4 1.22 6.19 18.63 21.74 4 1.59 2.58 6.17 12.14 5 1.593.72 6.32 15.29 20.29 4 1.71 2.79 14.21 20.24 4 2.46 3.46 16.19 17.51 41.53 2.75 13.34 22.28 4 0.79 1.24 2.34 8.64 3 1.73 2.25 10.49 4 1.482.18 17.64 19.72 3 0.41 2.41 10.1 3 1.32 12.74 15.45 3 2.9 12.50 19.25 41.72 2.18 12.75 21.11 3 0.40 1.34 2.43 4 1.57 2.71 8.76 11.29 3 0.7410.67 15.54 3 7.5 8.23 14.66 3 10.70 12.41 13.17 3 10.59 12.72 14.74 30.3 8.25 14.31 3 8.54 14.65 22.68 3 0.15 12.18 13.29 3 0.11 8.21 19.33 30.30 13.29 19.80 3 0.50 8.41 16.79 3 12.51 14.41 22.45 2 8.18 17.77 30.3 4.51 8.6 3 8.34 10.58 14.67 3 10.14 17.30 18.56 2 14.69 18.64 3 9.5812.59 15.11 3 0.74 12.48 14.38 3 0.41 10.52 15.16 3 12.58 16.63 20.80 30.8 12.2 18.25 2 0.64 20.35 3 0.68 11.4 12.26 3 0.39 12.66 22.61 3 11.2612.50 18.31 2 14.11 16.18 3 9.73 10.80 19.44 2 11.54 13.28 3 0.68 14.019.55 3 0.53 7.3 15.42 3 0.65 10.72 16.73 3 0.54 12.11 23.69 3 0.4412.15 17.70 3 12.57 16.48 18.61 3 7.48 14.30 18.72 2 7.80 10.47 3 0.412.23 19.72 3 9.59 13.4 17.69 2 9.66 18.22 3 12.52 16.53 19.60 2 8.3521.13 3 7.65 9.44 16.68 3 12.16 13.9 17.9 3 7.10 12.3 14.7 2 17.50 22.53 9.62 16.20 17.80

It should be noted that, Table 4 is merely an example table. In additionto the content shown in Table 4. Table 4 further includes a row index inthe check matrix for each row matrix in the 100-row matrix and atransmission code rate and a gap that correspond to each row matrix. Thegap may be a difference between performance in this embodiment of thisapplication and a decoding performance limit.

For example, if the first transmission code rate is 5/7, the matrixH_(MC) is shown in Table 1, and the matrix H_(IR) is a matrix of thefirst 100 rows in the 136-row matrix shown in Table 2, the first checkmatrix may be shown in FIG. 4a . In FIG. 4a , an empty block representsan all-zero matrix whose size is 81×81, an upper left corner is a 4×24matrix H_(MC), an upper right corner is a 4×4 all-zero matrix, a lowerleft corner is the first four rows of HR, and a lower right corner is a4×4 identity matrix. In this case, the first check matrix has a size of8 rows and 28 columns. Each entry in the first check matrix may beexpanded based on an 81×81 square submatrix to obtain a parity checkmatrix of 648 rows and 2268 columns corresponding to the first checkmatrix. If the first transmission code rate is a code rate other than ⅚,an upper left part of a check matrix H formed by the matrixes shown inTable 1 and Table 2 may be extracted in the foregoing manner, so thatthe extracted matrix supports the first transmission code rate.

For another example, if the first transmission code rate is 5/7, thematrix H_(MC) is shown in Table 1, and the matrix H_(IR) is the 100-rowmatrix shown in Table 3, the first check matrix may be shown in FIG. 4b. In FIG. 4b , an empty block represents an all-zero matrix whose sizeis 81×81, an upper left corner is a 4×24 matrix H_(MC), an upper rightcorner is a 4×4 all-zero matrix, a lower left corner is the first fourrows of H_(IR), that is, the first four rows of the 100-row matrix shownin Table 3, and a lower right corner is a 4×4 identity matrix. In thiscase, the first check matrix has a size of 8 rows and 28 columns. Eachentry in the first check matrix may be expanded based on an 81×81 squaresubmatrix to obtain a parity check matrix of 648 rows and 2268 columnscorresponding to the first check matrix. For another example, if thefirst transmission code rate is a code rate other than ⅚, an upper leftpart of a check matrix H formed by the matrixes shown in Table 1 andTable 3 may be extracted in the foregoing manner.

Step 303: The transmit end sends an encoded first codeword to a receiveend.

A code length of the first codeword may be (n+j×Z), and the firstcodeword includes the k information bits and (n+j×Z−k) redundant bits.For example, that the transmit end sends a first codeword to a receiveend may include: the transmit end modulates the first codeword, andsends the modulated first codeword to the receive end.

Based on the method shown in FIG. 3, the transmit end may extract, basedon a transmission code rate required for sending the information bits,corresponding check bits from the check matrix H obtained by extendingrows and columns of a check matrix in an existing standard, to performLDPC encoding on the information bits, thereby meeting a transmissioncode rate requirement, and improving data transmission reliability.

Correspondingly, after the receive end receives the modulated firstcodeword, the receive end may demodulate the modulated first codeword toobtain the first codeword, extract corresponding elements from the checkmatrix H based on the first transmission code rate to obtain the firstcheck matrix, and decode the first codeword based on the first checkmatrix.

The transmit end may indicate the first transmission code rate to thereceive end.

As described above, the check matrix H may be pre-stored at the receiveend. For a process in which the receive end extracts the correspondingelements from the check matrix H based on the first transmission coderate to obtain the first check matrix, refer to the description of step302. For a process in which the receive end decodes the first codewordbased on the first check matrix, refer to a conventional technology.Details are not described again.

Further, if the receive end determines that the decoding of the firstcodeword fails, that is, transmission of the first codeword fails, thetransmit end performs the first retransmission by sending newincremental redundant bits or new incremental redundant bits and some ofthe information bits to the receive end, so as to reduce a transmissioncode rate and obtain a better decoding effect. Specifically, the methodfurther includes the following steps.

The transmit end encodes the k information bits by using a second checkmatrix based on a second transmission code rate R satisfying R=k/(n+h×Z)to obtain an encoded second codeword, where h is an integer greater thanj and less than or equal to Q: a code length of the second codeword is(n+h×Z), and the second codeword includes the k information bits and(n+h×Z−k) redundant bits; and the (n+h×Z−k) redundant bits include the(n+j×Z−k) redundant bits in the first codeword, and the (n+j×Z−k)redundant bits are the first several bits in the (n+h×Z−k) redundantbits.

The transmit end sends the incremental redundant bits to the receiveend, or sends some of the k information bits and the incrementalredundant bits to the receive end, where the incremental redundant bitsare the (n+j×Z−k+₁)^(th) to the (n+h×Z−k)^(th) redundant bits in the(n+h×Z−k) redundant bits.

The second transmission code rate may be a rate at which the transmitend performs the first retransmission to the receive end. The transmitend may select, based on a current communications environment betweenthe transmit end and the receive end and another parameter, onetransmission code rate from preset transmission code rates as the secondtransmission code rate. The second transmission code rate is less thanthe first transmission code rate.

For example, the transmit end may extract elements from the first((n−k)/Z+h) rows and the first (n/Z+h) columns in the check matrix Hbased on the second transmission code rate to obtain the second checkmatrix. That the transmit end encodes the k information bits by using asecond check matrix based on a second transmission code rate Rsatisfying R=k/(n+h×Z) to obtain an encoded second codeword mayspecifically be: the transmit end expands each element in the secondcheck matrix based on a Z×Z square submatrix, and the transmit endperforms LDPC encoding on the k information bits based on a parity checkmatrix of ((n−k)+h×Z) rows and (n+h×Z) columns that is obtained byexpansion. For example, the transmit end may perform LDPC encoding onthe k information bits by using the parity check matrix of (n−k)+j×Z)rows and (n+j×Z) columns by referring to a conventional technology.Details are not described.

Correspondingly, after the receive end receives the incrementalredundant bits that are transmitted by the transmit end for the secondtime or some of the k information bits and the incremental redundantbits that are transmitted by the transmit end for the second time, thereceive end may combine the incremental redundant bits to an end of thefirst codeword to form a new codeword, for example, the second codeword.In addition, the receive end extracts corresponding elements from thecheck matrix H to obtain the second check matrix, and decodes the newcodeword based on the second check matrix.

Further, if the receive end determines that the decoding of the secondcodeword fails, that is, the first retransmission fails, the transmitend performs the second retransmission by sending new incrementalredundant bits or new incremental redundant bits and some of theinformation bits to the receive end, so as to reduce a transmission coderate and obtain a better decoding effect. Specifically, with referenceto the first retransmission, the method may further include thefollowing.

The transmit end encodes the k information bits by using a third checkmatrix based on a third transmission code rate R satisfying R=k/(n+w×Z)to obtain an encoded third codeword, where the third check matrix is asubmatrix of the first ((n−k)/Z+w) rows and the first (n/Z+w) columns inthe check matrix H. and w is an integer greater than h and less than orequal to Q; a code length of the third codeword is (n+w×Z), and thethird codeword includes the k information bits and (n+w×Z−k) redundantbits; and the (n+w×Z−k) redundant bits include the (n+h×Z−k) redundantbits in the second codeword, and the (n+h×Z−k) redundant bits are thefirst several bits in the (n+w×Z−k) redundant bits.

The transmit end sends the incremental redundant bits to the receiveend, or sends some of the k information bits and the incrementalredundant bits to the receive end, where the incremental redundant bitsare the (n+h×Z−k+1)^(th) to the (n+w×Z−k)^(th) redundant bits in the(n+w×Z−k) redundant bits.

The third transmission code rate may be a rate at which the transmit endperforms the second retransmission to the receive end. The transmit endmay select, based on a current communications environment between thetransmit end and the receive end and another parameter, one transmissioncode rate from the preset transmission code rates as the thirdtransmission code rate. The third transmission code rate is less thanthe second transmission code rate.

The transmit end may extract elements from the first ((n−k)/Z+w) rowsand the first (n/Z+w) columns in the check matrix H based on the thirdtransmission code rate to obtain the third check matrix. That thetransmit end encodes the k information bits by using a third checkmatrix based on a third transmission code rate R satisfying R=k/(n+w×Z)to obtain an encoded third codeword may specifically be: the transmitend expands each element in the third check matrix based on a Z×Z squaresubmatrix, and the transmit end performs LDPC encoding on the kinformation bits based on a parity check matrix of ((n−k)+w×Z) rows and(n+w×Z) columns that is obtained by expansion. For example, the transmitend may perform LDPC encoding on the k information bits by using theparity check matrix of (n−k)+j×Z) rows and (n+j×Z) columns by referringto a conventional technology. Details are not described.

Correspondingly, after the receive end receives the incrementalredundant bits that are transmitted by the transmit end for the thirdtime or some of the k information bits and the incremental redundantbits that are transmitted by the transmit end for the third time, thereceive end may combine the incremental redundant bits to an end of thesecond codeword to form a new codeword, for example, the third codeword.In addition, the receive end extracts corresponding elements from thecheck matrix H to obtain the third check matrix, and decodes the thirdcodeword based on the third check matrix. If the decoding succeeds, theprocess ends; or if the decoding fails, the receive end performsretransmission again, and the process ends when the decoding succeeds ora quantity of retransmissions reaches an upper limit.

For each retransmission process, refer to the foregoing descriptions ofthe first retransmission or the second retransmission. Details are notdescribed.

For example, n=1944, Z=81, k=1620, the matrix H_(MC) is an existingcheck matrix with a code length n of 1944 and a code rate of ⅚, therate-compatible check matrix H is a matrix of (4+100) rows and (24+100)columns, and the transmit end and the receive end successfully transmitthe information bits only after performing four transmissions with eachother. FIG. 5 and FIG. 6 are schematic diagrams of mutual communicationbetween the transmit end and the receive end by using an IR-HARQtechnology.

Refer to FIG. 5. During the first transmission, it is assumed that atransmission code rate R satisfies R=k/n=⅚. The transmit end extracts,based on the transmission code rate of ⅚, a submatrix of 4 rows and 24columns at an upper left corner of the rate-compatible check matrix H,that is, extracts the matrix H_(MC), performs LDPC encoding oninformation bits with a length of k by using the matrix H_(MC) to obtaina first codeword including the k information bits and check bits with alength of n−k, and modulates the first codeword for transmission to thereceive end. Correspondingly, as shown in FIG. 6, the receive enddirectly sends a demodulated log-likelihood ratio (LLR) 1 to a decoderfor decoding. In this case, a length of the LLR 1 sent to the decoder isn. The decoder at the receive end decodes the LLR 1 with a length of nby using the matrix H_(MC), and determines, by calculation based on adecoding result, whether a syndrome of the first codeword is 0. If yes,it indicates that the transmission succeeds: otherwise, the firstretransmission, that is, the second transmission, needs to be performed.

Refer to FIG. 5. During the first retransmission, it is assumed that atransmission code rate R satisfies R=k/(n+4×Z)= 5/7. The receive endextracts, based on the transmission code rate of 5/7, a submatrix of 8rows and 28 columns at the upper left corner of the rate-compatiblecheck matrix H, performs LDPC encoding on the information bits with thelength of k by using the extracted submatrix to obtain a second codewordincluding the k information bits and check bits with a length of(n−k+4×Z), and modulates 324 (4×Z=324) incremental redundant bitsobtained by comparing the check bits in the second codeword with thecheck bits in the first codeword, for transmission to the receive end.Correspondingly, as shown in FIG. 6, after receiving the modulatedincremental redundant bits, the receive end directly appends ademodulated LLR 2 to the LLR 1 to form (LLR 1, LLR 2) with a length of2268 (n+4×Z=2268). Then, the receive end sends (LLR 1, LLR 2) with thelength of 2268 to the decoder for decoding. The decoder at the receiveend decodes (LLR 1, LLR 2) with the length of 2268 by using thesubmatrix of 8 rows and 28 columns at the upper left corner of the checkmatrix H, and determines, by calculation based on a decoding result,whether a syndrome of the frame in the second transmission is 0. If yes,the transmission succeeds; otherwise, the second retransmission, thatis, the third transmission, needs to be performed.

Refer to FIG. 5. During the second retransmission, it is assumed that atransmission code rate R satisfies R=k/(n+6×Z)=⅔. The receive endextracts, based on the transmission code rate of ⅔, a submatrix of 10rows and 30 columns at the upper left corner of the rate-compatiblecheck matrix H, performs LDPC encoding on the information bits with thelength of k by using the extracted submatrix to obtain a third codewordincluding the k information bits and check bits with a length of(n−k+6-Z), and modulates 486 (6×Z=486) incremental redundant bitsobtained by comparing the check bits in the third codeword with thecheck bits in the second codeword, for transmission to the receive end.Correspondingly, as shown in FIG. 6, after receiving the modulatedincremental redundant bits, the receive end directly appends ademodulated LLR 3 to the LLR 2 to form (LLR 1, LLR 2, LLR 3) with alength of 2430 (n+6×Z=2430). Then, the receive end sends (LLR 1, LLR 2,LLR 3) with the length of 2430 to the decoder for decoding. The decoderat the receive end decodes (LLR 1, LLR 2, LLR 3) with the length of 2430by using the submatrix of 10 rows and 30 columns at the upper leftcorner of the check matrix H, and determines, by calculation based on adecoding result, whether a syndrome of the frame in the thirdtransmission is 0. If yes, the transmission succeeds; otherwise, thethird retransmission, that is, the fourth transmission, needs to beperformed.

Refer to FIG. 5. During the third retransmission, it is assumed that atransmission code rate R satisfies R=k/(n+12×Z)= 5/9. The receive endextracts, based on the transmission code rate of 5/9, a submatrix of 16rows and 36 columns at the upper left corner of the rate-compatiblecheck matrix H, performs LDPC encoding on the information bits with thelength of k by using the extracted submatrix to obtain a fourth codewordincluding the k information bits and check bits with a length of(n−k+12×Z), and modulates 972 (12×Z=972) incremental redundant bitsobtained by comparing the check bits in the fourth codeword with thecheck bits in the third codeword, for transmission to the receive end.Correspondingly, as shown in FIG. 6, after receiving the modulatedincremental redundant bits, the receive end directly appends ademodulated LLR 4 to the LLR 3 to form (LLR 1, LLR 2, LLR 3, LLR 4) witha length of 2916 (n+12×Z=2916). Then, the receive end sends (LLR 1, LLR2, LLR 3, LLR 4) with the length of 2916 to the decoder for decoding.The decoder at the receive end decodes (LLR 1, LLR 2, LLR 3, LLR 4) withthe length of 2916 by using the submatrix of 16 rows and 36 columns atthe upper left corner of the check matrix H, and determines, bycalculation based on a decoding result, whether a syndrome of the framein the fourth transmission is 0. If yes, the transmission succeeds.

It should be noted that, FIG. 5 and FIG. 6 illustrate IR-HARQ by usingonly an example in which the transmit end transmits incrementalredundant bits to the receive end during retransmission. It can beunderstood that, during retransmission, the transmit end may furthertransmit some information bits to the receive end in addition to theincremental redundant bits. This is not limited.

To describe performance of the LDPC encoding scheme provided in theembodiments of this application, FIG. 7 illustrates a diagram of asimulation curve of a system throughput of the encoding scheme providedin the embodiments of this application, a simulation curve of a systemthroughput of an encoding scheme used in an IR-HARQ process in anexisting 5G communications system, and a simulation curve of a systemthroughput of CC-HARQ performed in a WLAN communications system in acommunications scenario in which a channel transmission latency L isequal to 200 and a maximum quantity of channel transmissions is 4. Asshown in FIG. 7, a horizontal axis is a signal-to-noise ratio (SNR)(dB), and a vertical axis is a system throughput. It can be learned fromFIG. 7 that, the throughput corresponding to the encoding schemeprovided in the embodiments of this application is higher than thethroughput achieved by performing CC-HARQ in a WLAN communicationssystem. In addition, the throughput corresponding to the encoding schemeprovided in the embodiments of this application is close to thethroughput of LDPC encoding in a 5G communications system, and thethroughput of 5G LDPC is close to a throughput in an ideal case. It canbe learned from FIG. 7 that, the throughput corresponding to theencoding scheme provided in the embodiments of this application isrelatively high, thereby improving overall system performance.

For another example, FIG. 8 illustrates a diagram of a simulation curveof a system throughput of the encoding scheme provided in theembodiments of this application, a simulation curve of a systemthroughput of an encoding scheme used in an IR-HARQ process in anexisting 5G communications system, and a simulation curve of a systemthroughput of CC-HARQ performed in a WLAN communications system in acommunications scenario in which a channel transmission latency L isequal to 200 and a maximum quantity of channel transmissions is 4. Asshown in FIG. 8, a horizontal axis is an SNR (dB), and a vertical axisis a system throughput. It can be learned from FIG. 8 that, thethroughput corresponding to the encoding scheme provided in theembodiments of this application is higher than the throughput achievedby performing CC-HARQ in a WLAN communications system. In addition, thethroughput corresponding to the encoding scheme provided in theembodiments of this application is close to the throughput of LDPCencoding in a 5G communications system, and the throughput of 5G LDPC isclose to a throughput in an ideal case. It can be learned from FIG. 8that, the throughput corresponding to the encoding scheme provided inthe embodiments of this application is relatively high, therebyimproving overall system performance.

The foregoing mainly describes the solutions provided in embodiments ofthis application from a perspective of interaction between nodes. It maybe understood that, to implement the foregoing functions, the nodesinclude corresponding hardware structures and/or software modules forperforming the functions. A person skilled in the art should easily beaware that, in combination with the examples described in embodimentsdisclosed in this specification, algorithm steps may be implemented byhardware or a combination of hardware and computer software in thisapplication. Whether a specific function is performed by hardware orhardware driven by computer software depends on particular applicationsand design constraints of the technical solutions. A person skilled inthe art may use different methods to implement the described functionsfor each particular application, but it should not be considered thatthe implementation goes beyond the scope of this application.

In embodiments of this application, division into function modules maybe performed on the transmit end and the receive end based on theforegoing method examples. For example, each function module may beobtained through division based on each corresponding function, or twoor more functions may be integrated into one processing module. Theintegrated module may be implemented in a form of hardware, or may beimplemented in a form of a software function module. It should be notedthat, in embodiments of this application, division into the modules isan example, and is merely logical function division. In actualimplementation, another division manner may be used.

FIG. 9 is a diagram of a structure of a communications apparatus 90. Thecommunications apparatus 90 may be a transmit end, or a chip or asystem-on-a-chip in a transmit end. The communications apparatus 90 maybe configured to perform functions of the transmit end in the foregoingembodiments. In an implementation, the communications apparatus 90 shownin FIG. 9 includes a processing unit 901 and a sending unit 902.

The processing unit 901 is configured to obtain k information bits, andperform LDPC encoding on the k information bits by using a first checkmatrix based on a first transmission code rate R satisfying R=k/(n+j×Z),where the first check matrix is a submatrix of the first ((n−k)/Z+j)rows and the first (n/Z+j) columns in a check matrix H. For example, theprocessing unit 901 can support the communications apparatus 90 inperforming step 301 and step 302.

The sending unit 902 is configured to send an encoded first codewordincluding the k information bits and (n−k+j×Z) redundant bits to areceive end. For example, the sending unit 902 may support thecommunications apparatus 90 in performing step 303.

Further, the processing unit 901 is further configured to: whentransmission of the first codeword fails, encode the k information bitsby using a second check matrix based on a second transmission code rateR satisfying R=k/(n+h×Z) to obtain a second codeword, where the secondcheck matrix is a submatrix of the first ((n−k)/Z+h) rows and the first(n/Z+h) columns in the check matrix H, a code rate of the second checkmatrix is equal to the second transmission code rate, and h is aninteger greater than j and less than or equal to Q; and a code length ofthe second codeword is (n+h×Z), and the second codeword includes the kinformation bits and (n−k+h×Z) redundant bits.

The sending unit 902 is further configured to send incremental redundantbits to the receive end, or send some of the k information bits andincremental redundant bits to the receive end, where the incrementalredundant bits are the (n−k+j×Z+1)^(th) to the (n−k+h×Z)^(th) redundantbits in the (n−k+h×Z) redundant bits.

n is an integer greater than 0, j is an integer greater than or equal to0, the check matrix H is a matrix of ((n−k)/Z+Q) rows and (n/Z+Q)columns, Q is an integer greater than or equal to j, each element in thecheck matrix H represents one Z×Z square submatrix, and the squaresubmatrix is a cyclic permutation matrix of an identity matrix or anall-zero matrix; the check matrix H includes a matrix H_(MC), a matrixH_(IR) of Q rows and 24 columns, an all-zero matrix of 4 rows and Qcolumns, and an identity matrix of Q rows and Q columns; and the matrixH_(MC) is a matrix of (n−k)/Z rows and n/Z columns, the matrix H_(MC) islocated at an upper left corner of the check matrix H, the matrix H_(IR)of Q rows and 24 columns is located at a lower left corner of the checkmatrix H, the all-zero matrix of 4 rows and Q columns is located at anupper right corner of the check matrix H, and the identity matrix of Qrows and Q columns is located at a lower right corner of the checkmatrix H, that is, the check matrix H is a matrix obtained by extendingrows and columns of the matrix H_(MC).

In an example, the matrix H_(IR) of Q rows and 24 columns may includeany Q rows in the 136-row matrix shown in Table 2, for example, may be amatrix of the first Q rows in Table 2, a matrix of the last Q rows inTable 2, a matrix of Q consecutive rows starting from the q^(th) row inTable 2, or a matrix of Q non-consecutive rows starting from the q^(th)row in Table 2, where q is an integer greater than or equal to 1.

In another example, the matrix H_(IR) of Q rows and 24 columns mayinclude any Q rows in the 100-row matrix shown in Table 3, for example,may be a matrix of the first Q rows in Table 3, a matrix of the last Qrows in Table 3, a matrix of Q consecutive rows starting from the q*^(h)row in Table 3, or a matrix of Q non-consecutive rows starting from theq^(th) row in Table 3, where q is an integer greater than or equal to 1.

Specifically, all related content of the steps in the method embodimentshown in FIG. 3 may be cited in function descriptions of correspondingfunction modules. Details are not described herein again. Thecommunications apparatus 90 is configured to perform a function of aterminal in the LDPC encoding method shown in FIG. 3, and therefore, canachieve an effect same as that of the LDPC encoding method.

In another implementation, the communications apparatus 90 shown in FIG.9 includes a processing module and a communications module. Theprocessing module is configured to control and manage an action of thecommunications apparatus 90. For example, the processing module mayintegrate a function of the processing unit 901, and may be configuredto support the communications apparatus 90 in performing step 301, step302, and another process of the technology described in thisspecification. The communications module may integrate a function of thesending unit 902, and may be configured to support the communicationsapparatus 90 in performing step 303 and communicating with anothernetwork entity, for example, communicating with a function module or anetwork entity shown in FIG. 2. The communications apparatus 90 mayfurther include a storage module, configured to store program code ofthe communications apparatus 90 and the check matrix H.

The processing module may be a processor or a controller. The processingmodule may implement or execute various example logical blocks, modules,and circuits described with reference to content disclosed in thisapplication. Alternatively, the processor may be a combination ofprocessors implementing a computing function, for example, a combinationof one or more microprocessors, or a combination of a DSP and amicroprocessor. The communications module may be a transceiver circuit,or the like. The storage module may be a memory. When the processingmodule is a processor, the communications module is a transceivercircuit, and the storage module is a memory, the communicationsapparatus 90 in this embodiment of this application may be thecommunications apparatus shown in FIG. 2.

An embodiment of this application further provides a computer-readablestorage medium. All or some of the processes in the foregoing methodembodiments may be completed by a computer program instructing relatedhardware. The program may be stored in the foregoing computer storagemedium. When the program is executed, the processes of the foregoingmethod embodiments may be performed. The computer-readable storagemedium may be an internal storage unit of the AP apparatus according toany one of the foregoing embodiments, for example, including a datatransmit end and/or a data receive end. For example, thecomputer-readable storage medium may be a hard disk or a memory of theAP apparatus. The computer-readable storage medium may alternatively bean external storage device of the foregoing AP apparatus, for example, aplug-in hard disk, a smart media card (SMC), a secure digital (SD) card,or a flash card that is provided on the AP apparatus. Further, thecomputer-readable storage medium may alternatively include both aninternal storage unit and an external storage device of the foregoing APapparatus. The computer-readable storage medium is configured to storethe computer program and other programs and data that are required bythe foregoing AP apparatus. The computer-readable storage medium may befurther configured to temporarily store data that has been output or isto be output.

It should be noted that, in the specification and the accompanyingdrawings of this application, the terms “first”, “second”, and the likeare used to distinguish between different objects, rather than todescribe a specific order. In addition, the terms “include”, “have”, andany other variant thereof are intended to cover non-exclusive inclusion.For example, a process, method, system, product, or device that includesa series of steps or units is not limited to the listed steps or units,but optionally further includes an unlisted step or unit, or optionallyfurther includes another inherent step or unit of the process, method,product, or device.

It should be understood that, in this application, “at least one (item)”means one or more, “a plurality of” means two or more, “at least two(items)” means two, three, or more, and “and/or” is used to describe anassociation relationship between associated objects, and indicates thatthere may be three relationships. For example. “A and/or B” may indicatethat only A exists, only B exists, and both A and B exist, where A and Bmay be singular or plural. The character “/” generally indicates an “or”relationship between the associated objects. “At least one of thefollowing items (pieces)” or a similar expression thereof indicates anycombination of these items, including a single item (piece) or anycombination of a plurality of items (pieces). For example, at least one(piece) of a, b, or c may represent: a, b, c, “a and b”, “a and c”, “band c”, or “a, b, and c”, where a, b, and c may be singular or plural.

It should be understood that in embodiments of this application, “Bcorresponding to A” indicates that B is associated with A. For example,B may be determined based on A. However, it should be further understoodthat B is determined based on A does not mean that B is determined basedon only A, that is, B may alternatively be determined based on A and/orother information. In addition, in embodiments of this application,“connection” means various connection manners such as a directconnection or an indirect connection, for implementing communicationbetween devices. This is not limited in embodiments of this application.

Unless otherwise specified, “transmit/transmission” in embodiments ofthis application refers to bidirectional transmission, and includes asending action and/or a receiving action. Specifically,“transmit/transmission” in embodiments of this application includes datasending, data receiving, or data sending and data receiving. In otherwords, data transmission herein includes uplink and/or downlink datatransmission. The data may include a channel and/or a signal. The uplinkdata transmission is uplink channel transmission and/or uplink signaltransmission, and the downlink data transmission is downlink channeltransmission and/or downlink signal transmission. In embodiments of thisapplication, a “network” and a “system” convey a same concept, and acommunications system is a communications network.

The foregoing descriptions about the implementations allow a personskilled in the art to clearly understand that, for the purpose ofconvenient and brief description, division into the foregoing functionmodules is merely used as an example for illustration. In actualapplication, the foregoing functions can be allocated to differentfunction modules and implemented based on a requirement, that is, aninner structure of the apparatus is divided into different functionmodules to implement all or some of the functions described above.

In several embodiments provided in this application, it should beunderstood that the disclosed apparatus and method may be implemented inother manners. For example, the described apparatus embodiments aremerely examples. For example, division into the modules or units ismerely logical function division. There may be another division mannerin actual implementation. For example, a plurality of units orcomponents may be combined or may be integrated into another apparatus,or some features may be ignored or not be performed. In addition, thedisplayed or discussed mutual couplings or direct couplings orcommunication connections may be implemented through some interfaces.The indirect couplings or communication connections between theapparatuses or units may be implemented in electronic, mechanical, orother forms.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may be one or more physicalunits, may be located in one place, or may be distributed at differentplaces. Some or all of the units may be selected based on actualrequirements to achieve the objectives of the solutions of theembodiments.

In addition, function units in embodiments of this application may beintegrated into one processing unit, or each of the units may existalone physically, or two or more units may be integrated into one unit.The integrated unit may be implemented in a form of hardware, or may beimplemented in a form of a software function unit.

When the integrated unit is implemented in a form of a software functionunit and sold or used as an independent product, the integrated unit maybe stored in a readable storage medium. Based on such an understanding,the technical solutions of the embodiments of this applicationessentially, or the part contributing to the conventional technology, orall or some of the technical solutions may be implemented in a form of asoftware product. The software product is stored in a storage medium andincludes several instructions for instructing a device, where forexample, the device may be a single-chip microcomputer or a chip, or aprocessor to perform all or some of the steps of the methods in theembodiments of this application. The foregoing storage medium includes:any medium that can store program code, such as a USB flash drive, aremovable hard disk, a ROM, a RAM, a magnetic disk, or an optical disc.

The foregoing descriptions are merely specific implementations of thisapplication, but are not intended to limit the protection scope of thisapplication. Any variation or replacement within the technical scopedisclosed in this application shall fall within the protection scope ofthis application. Therefore, the protection scope of this applicationshall be subject to the protection scope of the claims.

What is claimed is:
 1. A low-density parity-check (LDPC) encodingmethod, wherein the method comprises: obtaining, by a transmit end, kinformation bits, wherein k is an integer greater than 0; andperforming, by the transmit end, LDPC encoding on the k information bitsby using a first check matrix based on a first transmission code rate Rsatisfying R=k/(n+j×Z), and sending an encoded first codeword to areceive end, wherein: the first check matrix is a submatrix of the first((n−k)/Z+j) rows and the first (n/Z+j) columns in a check matrix H, anda code rate of the first check matrix is equal to the first transmissioncode rate; n is an integer greater than 0, j is an integer greater thanor equal to 0, and Z is an integer greater than 0: the check matrix H isa matrix of ((n−k)/Z+Q) rows and (n/Z+Q) columns, Q is an integergreater than or equal to j, each element in the check matrix Hrepresents one Z×Z square submatrix, and the square submatrix is acyclic permutation matrix of an identity matrix or an all-zero matrix;the check matrix H comprises a matrix H_(MC), a matrix H_(IR) of Q rowsand 24 columns, an all-zero matrix of 4 rows and Q columns, and anidentity matrix of Q rows and Q columns; the matrix H_(MC) is a matrixof (n−k)/Z rows and n/Z columns, the matrix H_(MC) is located at anupper left corner of the check matrix H, the matrix H_(IR) of Q rows and24 columns is located at a lower left corner of the check matrix H, theall-zero matrix of 4 rows and Q columns is located at an upper rightcorner of the check matrix H, and the identity matrix of Q rows and Qcolumns is located at a lower right corner of the check matrix H; and acode length of the first codeword is (n+j×Z), and the first codewordcomprises the k information bits and (n−k+j×Z) redundant bits.
 2. Themethod according to claim 1, wherein the method further comprises: whentransmission of the first codeword fails, encoding, by the transmit end,the k information bits by using a second check matrix based on a secondtransmission code rate R satisfying R=k/(n+h×Z) to obtain a secondcodeword, wherein the second check matrix is a submatrix of the first((n−k)/Z+h) rows and the first (n/Z+h) columns in the check matrix H, acode rate of the second check matrix is equal to the second transmissioncode rate, h is an integer greater than j and less than or equal to Q, acode length of the second codeword is (n+h×Z), and the second codewordcomprises the k information bits and (n−k+h×Z) redundant bits; andsending, by the transmit end, incremental redundant bits to the receiveend, or sending some of the k information bits and incremental redundantbits to the receive end, wherein the incremental redundant bits are the(n−k+j×Z+1)^(th) to the (n−k+h×Z)^(th) redundant bits in the (n−k+h×Z)redundant bits.
 3. The method according to claim 1, wherein the matrixH_(IR) of Q rows and 24 columns is any Q-row matrix in a preset 136-rowmatrix, each row in the preset 136-row matrix comprises 24 elements,each element represents one square submatrix whose size is Z×Z, a nullelement in each row represents an all-zero matrix, a specific value of anon-null element in each row is a cyclic permutation value of anidentity matrix, and the preset 136-row matrix is as follows: 25 24 6 4773 23 16 49 30 16 47 19 65 40 44 0 60 71 56 53 55 24 55 39 79 68 14 4371 18 8 25 18 16 73 35 17 53 30 13 57 47 52 5 78 13 31 77 13 10 53 23 6648 71 11 4 66 10 9 10 37 18 52 68 2 43 75 73 12 55 29 33 49 0 69 62 5533 4 51 39 24 33 7 42 80 31 60 52 44 69 41 19 37 10 61 28 9 27 49 61 5430 69 56 18 24 68 39 34 49 47 40 35 43 72 27 45 52 34 55 9 33 58 68 7738 52 51 45 40 40 20 19 71 4 9 62 26 26 61 45 60 21 6 63 53 79 4 74 1957 40 16 28 65 37 43 40 52 51 78 79 60 11 40 52 79 46 70 51 70 80 20 4258 6 4 14 31 80 5 20 68 37 32 75 28 74 42 16 75 80 63 35 52 14 62 8 2945 26 57 56 24 40 33 51 17 32 80 2 49 78 12 24 55 34 80 4 36 24 64 20 5638 77 50 47 21 34 65 69 17 44 59 63 10 55 58 68 30 69 7 11 59 25 76 8 3911 49 67 39 26 57 73 24 45 42 1 60 73 73 56 77 10 3 39 61 44 70 68 7 4378 20 55 76 3 37 59 7 38 70 64 41 63 31 63 2 5 60 78 57 10 67 17 17 0 4659 51 7 33 22 27 4 19 9 6 0 43 38 64 5 63 73 55 7 44 12 21 31 28 57 2 2832 65 45 2 41 53 60 62 67 65 56 17 14 53 1 20 31 34 21 0 65 63 32 14 3911 58 18 75 43 74 25 75 0 65 6 80 67 16 58 76 2 76 2 70 70 19 5 26 61 4616 70 20 73 21 66 29 50 7 50 78 7 51 16 75 69 61 77 35 36 4 41 73 14 1720 4 17 76 23 68 8 6 52 70 55 37 50 44 6 54 16 55 14 51 63 70 65 13 2564 4 74 80 79 45 48 58 34 25 34 52 30 10 16 36 30 65 54 41 73 53 8 51 5630 5 43 69 55 42 14 7 74 47 63 21 74 20 11 8 38 60 75 73 40 29 14 44 7341 9 62 24 25 9 39 6 33 17 66 68 72 74 58 44 68 1 76 71 1 70 44 13 74 1648 50 51 56 53 72 12 70 80 1 4 36 30 44 27 42 50 45 79 64 62 79 59 76 7742 71 17 14 58 31 44 21 56 10 74 54 8


4. The method according to claim 1, wherein the matrix H_(IR) of Q rowsand 24 columns is any Q-row matrix in a preset 100-row matrix, each rowin the preset 100-row matrix comprises 24 elements, each elementrepresents one square submatrix whose size is Z×Z, a null element ineach row represents an all-zero matrix, a specific value of a non-nullelement in each row is a cyclic permutation value of an identity matrix,and the preset 100-row matrix is as follows: 60 15 34 80 20 29 39 22 777 7 72 79 69 49 75 8 2 56 22 58 18 47 21 80 38 50 75 32 21 26 30 36 4467 63 2 55 18 63 78 44 67 14 35 73 9 56 5 9 45 67 50 25 8 53 45 28 50 6234 8 4 76 80 50 13 40 32 0 20 47 38 55 45 67 71 57 38 47 79 7 76 27 3349 58 19 26 31 39 68 17 6 76 24 69 3 43 40 34 37 42 1 10 59 47 66 63 7426 47 3 53 67 67 46 69 56 35 36 54 17 7 26 77 24 43 32 36 9 76 33 78 1445 0 59 39 4 4 54 31 31 48 39 33 32 34 46 47 6 69 22 66 64 10 77 42 2362 65 43 43 6 48 16 29 23 3 11 44 34 70 59 49 16 1 77 19 8 10 17 44 2018 17 17 71 16 4 69 27 18 36 0 52 43 42 39 56 31 14 50 9 22 38 64 80 4380 59 34 48 31 22 77 71 21 54 41 65 58 78 47 56 70 21 13 8 41 22 19 6374 59 58 17 14 59 72 32 29 29 71 79 21 24 46 46 19 51 53 75 34 28 79 2434 64 73 25 49 48 18 64 72 41 41 1 32 74 45 9 50 25 72 18 75 11 40 34 4357 71 76 29 74 67 54 5 23 66 70 41 17 59 72 74 3 25 31 54 65 68 15 18 2911 21 33 30 29 80 50 41 79 51 41 45 18 77 3 51 6 34 58 67 14 30 56 69 6458 59 11 74 48 38 41 52 16 58 63 80 8 2 25 64 35 68 4 26 39 66 61 26 5031 11 18 73 80 44 54 28 68 0 55 53 3 42 65 72 73 54 11 69 44 15 70 57 4861 48 30 72 80 47 4 23 72 59 4 69 66 22 52 53 60 35 13 65 44 68 16 9 910 3 7 50 5 62 20 80


5. A low-density parity-check (LDPC) decoding method, wherein the methodcomprises: obtaining, by a receive end, an encoded first codeword; anddecoding, by the receive end, the encoded first codeword based on afirst check matrix, wherein a code length of the encoded first codewordis (n+j×Z), and the encoded first codeword comprises k information bitsand (n−k+j×Z) redundant bits, wherein: the first check matrix is asubmatrix of the first ((n−k)/Z+j) rows and the first (n/Z+j) columns ina check matrix H, and a code rate of the first check matrix is equal toa first transmission code rate; n is an integer greater than 0, j is aninteger greater than or equal to 0, and Z is an integer greater than 0;the check matrix H is a matrix of ((n−k)/Z+Q) rows and (n/Z+Q) columns,Q is an integer greater than or equal to j, each element in the checkmatrix H represents one Z×Z square submatrix, and the square submatrixis a cyclic permutation matrix of an identity matrix or an all-zeromatrix; the check matrix H comprises a matrix HMC, a matrix HIR of Qrows and 24 columns, an all-zero matrix of 4 rows and Q columns, and anidentity matrix of Q rows and Q columns; and the matrix HMC is a matrixof (n−k)/Z rows and n/Z columns, the matrix HMC is located at an upperleft corner of the check matrix H, the matrix H_(IR) of Q rows and 24columns is located at a lower left corner of the check matrix H, theall-zero matrix of 4 rows and Q columns is located at an upper rightcorner of the check matrix H, and the identity matrix of Q rows and Qcolumns is located at a lower right corner of the check matrix H.
 6. Themethod according to claim 5, wherein the method further comprises:obtaining, by the receive end, incremental redundant bits that aretransmitted by a transmit end for a second time or some of the kinformation bits and the incremental redundant bits that are transmittedby the transmit end; combining, by the receive end, the incrementalredundant bits to an end of the first codeword to form a secondcodeword; and decoding, by the receive end, the second codeword based ona second check matrix, wherein the second check matrix is a submatrix ofthe first ((n−k)/Z+h) rows and the first (n/Z+h) columns in the checkmatrix H, a code rate of the second check matrix is equal to a secondtransmission code rate, and h is an integer greater than j and less thanor equal to Q.
 7. The method according to claim 5, wherein the matrixH_(IR) of Q rows and 24 columns is any Q-row matrix in a preset 136-rowmatrix, each row in the preset 136-row matrix comprises 24 elements,each element represents one square submatrix whose size is Z×Z, a nullelement in each row represents an all-zero matrix, a specific value of anon-null element in each row is a cyclic permutation value of anidentity matrix, and the preset 136-row matrix is as follows: 25 24 6 4773 23 16 49 30 16 47 19 65 40 44 0 60 71 56 53 55 24 55 39 79 68 14 4371 18 8 25 18 16 73 35 17 53 30 13 57 47 52 5 78 13 31 77 13 10 53 23 6648 71 11 4 66 10 9 10 37 18 52 68 2 43 75 73 12 55 29 33 49 0 69 62 5533 4 51 39 24 33 7 42 80 31 60 52 44 69 41 19 37 10 61 28 9 27 49 61 5430 69 56 18 24 68 39 34 49 47 40 35 43 72 27 45 52 34 55 9 33 58 68 7738 52 51 45 40 40 20 19 71 4 9 62 26 26 61 45 60 21 6 63 53 79 4 74 1957 40 16 28 65 37 43 40 52 51 78 79 60 11 40 52 79 46 70 51 70 80 20 4258 6 4 14 31 80 5 20 68 37 32 75 28 74 42 16 75 80 63 35 52 14 62 8 2945 26 57 56 24 40 33 51 17 32 80 2 49 78 12 24 55 34 80 4 36 24 64 20 5638 77 50 47 21 34 65 69 17 44 59 63 10 55 58 68 30 69 7 11 59 25 76 8 3911 49 67 39 26 57 73 24 45 42 1 60 73 73 56 77 10 3 39 61 44 70 68 7 4378 20 55 76 3 37 59 7 38 70 64 41 63 31 63 2 5 60 78 57 10 67 17 17 0 4659 51 7 33 22 27 4 19 9 6 0 43 38 64 5 63 73 55 7 44 12 21 31 28 57 2 2832 65 45 2 41 53 60 62 67 65 56 17 14 53 1 20 31 34 21 0 65 63 32 14 3911 58 18 75 43 74 25 75 0 65 6 80 67 16 58 76 2 76 2 70 70 19 5 26 61 4616 70 20 73 21 66 29 50 7 50 78 7 51 16 75 69 61 77 35 36 4 41 73 14 1720 4 17 76 23 68 8 6 52 70 55 37 50 44 6 54 16 55 14 51 63 70 65 13 2564 4 74 80 79 45 48 58 34 25 34 52 30 10 16 36 30 65 54 41 73 53 8 51 5630 5 43 69 55 42 14 7 74 47 63 21 74 20 11 8 38 60 75 73 40 29 14 44 7341 9 62 24 25 9 39 6 33 17 66 68 72 74 58 44 68 1 76 71 1 70 44 13 74 1648 50 51 56 53 72 12 70 80 1 4 36 30 44 27 42 50 45 79 64 62 79 59 76 7742 71 17 14 58 31 44 21 56 10 74 54 8


8. The method according to claim 5, wherein the matrix H_(IR) of Q rowsand 24 columns is any Q-row matrix in a preset 100-row matrix, each rowin the preset 100-row matrix comprises 24 elements, each elementrepresents one square submatrix whose size is Z×Z, a null element ineach row represents an all-zero matrix, a specific value of a non-nullelement in each row is a cyclic permutation value of an identity matrix,and the preset 100-row matrix is as follows: 60 15 34 80 20 29 39 22 777 7 72 79 69 49 75 8 2 56 22 58 18 47 21 80 38 50 32 21 26 30 36 44 6763 2 55 18 63 78 44 67 14 35 73 9 56 5 9 45 67 50 25 8 53 45 28 50 62 348 4 76 80 50 13 40 32 0 20 47 38 55 45 67 71 57 38 47 79 7 76 27 33 4958 19 26 31 39 68 17 6 76 24 69 3 43 40 34 37 42 1 10 59 47 66 63 74 2647 3 53 67 67 46 69 56 35 36 54 17 7 26 77 24 43 32 36 9 76 3 78 14 45 059 39 4 4 54 31 31 48 39 33 32 34 46 47 6 69 22 66 64 10 77 42 23 62 6543 43 6 48 16 29 23 3 11 44 34 70 59 49 16 1 77 19 8 10 17 44 20 18 1717 71 16 4 69 27 18 36 0 52 43 42 39 56 31 14 50 9 22 38 64 80 43 80 5934 48 31 22 77 71 21 54 41 65 58 78 47 56 70 21 13 8 41 22 19 63 74 5958 17 14 59 72 32 29 29 71 79 21 24 46 46 19 51 53 75 34 28 79 24 34 6473 25 49 48 18 64 72 41 41 1 32 74 45 9 50 25 72 18 75 11 40 34 43 57 7176 29 74 67 54 5 23 66 70 41 17 59 72 74 3 25 31 54 65 68 15 18 29 11 2133 30 29 80 50 41 79 51 41 45 18 77 3 51 6 34 58 67 14 30 56 69 64 58 5911 74 48 38 41 52 16 58 63 80 8 2 25 64 35 68 4 26 39 66 61 26 50 31 1118 73 80 44 54 28 68 0 55 53 3 42 65 72 73 54 11 69 44 15 70 57 48 61 4830 72 80 47 4 23 72 59 4 69 66 22 52 53 60 35 13 65 44 68 16 9 9 10 3 750 5 62 20 80


9. A transmit end, wherein the transmit end comprises: at least oneprocessor; and one or more memories coupled to the at least oneprocessor and storing programming instructions for execution by the atleast one processor to obtain k information bits, and performlow-density parity-check (LDPC) encoding on the k information bits byusing a first check matrix based on a first transmission code rate Rsatisfying R=k/(n+j×Z), wherein: k is an integer greater than 0; thefirst check matrix is a submatrix of the first ((n−k)/Z+j) rows and thefirst (n/Z+j) columns in a check matrix H, and a code rate of the firstcheck matrix is equal to the first transmission code rate; n is aninteger greater than 0, j is an integer greater than or equal to 0, andZ is an integer greater than 0; the check matrix H is a matrix of((n−k)/Z+Q) rows and (n/Z+Q) columns, Q is an integer greater than orequal to j, each element in the check matrix H represents one Z×Z squaresubmatrix, and the square submatrix is a cyclic permutation matrix of anidentity matrix or an all-zero matrix, the check matrix H comprises amatrix H_(MC), a matrix H_(IR) of Q rows and 24 columns, an all-zeromatrix of 4 rows and Q columns, and an identity matrix of Q rows and Qcolumns; and the matrix H_(MC) is a matrix of (n−k)/Z rows and n/Zcolumns, the matrix H_(MC) is located at an upper left corner of thecheck matrix H, the matrix H_(IR) of Q rows and 24 columns is located ata lower left corner of the check matrix H, the all-zero matrix of 4 rowsand Q columns is located at an upper right corner of the check matrix H,and the identity matrix of Q rows and Q columns is located at a lowerright corner of the check matrix H; and a transmitter, the transmitterconfigured to send an encoded first codeword to a receive end, wherein acode length of the first codeword is (n+j×Z), and the first codewordcomprises the k information bits and (n−k+j Z) redundant bits.
 10. Thetransmit end according to claim 9, wherein: the programming instructionsare for execution by the at least one processor to encode the kinformation bits by using a second check matrix based on a secondtransmission code rate R satisfying R=k/(n+h×Z) to obtain a secondcodeword when transmission of the first codeword fails, wherein thesecond check matrix is a submatrix of the first ((n−k)/Z+h) rows and thefirst (n/Z+h) columns in the check matrix H, a code rate of the secondcheck matrix is equal to the second transmission code rate, h is aninteger greater than j and less than or equal to Q, a code length of thesecond codeword is (n+h×Z), and the second codeword comprises the kinformation bits and (n−k+h×Z) redundant bits; and the transmitter isfurther configured to send incremental redundant bits to the receiveend, or send some of the k information bits and incremental redundantbits to the receive end, wherein the incremental redundant bits are the(n−k+j×Z+1)^(th) to the (n−k+h×Z)^(th) redundant bits in the (n−k+h×Z)redundant bits.
 11. The transmit end according to claim 9, wherein thematrix H_(IR) of Q rows and 24 columns is any Q-row matrix in a preset136-row matrix, each row in the preset 136-row matrix comprises 24elements, each element represents one square submatrix whose size isZ×Z, a null element in each row represents an all-zero matrix, aspecific value of a non-null element in each row is a cyclic permutationvalue of an identity matrix, and the preset 136-row matrix is asfollows: 25 24 6 47 73 23 16 49 30 16 47 19 65 40 44 0 60 71 56 53 55 2455 39 79 68 14 43 71 18 8 25 18 16 73 35 17 53 30 13 57 47 52 5 78 13 3177 13 10 53 23 66 48 71 11 4 66 10 9 10 37 18 52 68 2 43 75 73 12 55 2933 49 0 69 62 55 33 4 51 39 24 33 7 42 80 31 60 52 44 69 41 19 37 10 6128 9 27 49 61 54 30 69 56 18 24 68 39 34 49 47 40 35 43 72 27 45 52 3455 9 33 58 68 77 38 52 51 45 40 40 20 19 71 4 9 62 26 26 61 45 60 21 663 53 79 4 74 19 57 40 16 28 65 37 43 40 52 51 78 79 60 11 40 52 79 4670 51 70 80 20 42 58 6 4 14 31 80 5 20 68 37 32 75 28 74 42 16 75 80 6335 52 14 62 8 29 45 26 57 56 24 40 33 51 17 32 80 2 49 78 12 24 55 34 804 36 24 64 20 56 38 77 50 47 21 34 65 69 17 44 59 63 10 55 58 68 30 69 711 59 25 76 8 39 11 49 67 39 26 57 73 24 45 42 1 60 73 73 56 77 10 3 3961 44 70 68 7 43 78 20 55 76 3 37 59 7 38 70 64 41 63 31 63 2 5 60 78 5710 67 17 17 0 46 59 51 7 33 22 27 4 19 9 6 0 43 38 64 5 63 73 55 7 44 1221 31 28 57 2 28 32 65 45 2 41 53 60 62 67 65 56 17 14 53 1 20 31 34 210 65 63 32 14 39 11 58 18 75 43 74 25 75 0 65 6 80 67 16 58 76 2 76 2 7070 19 5 26 61 46 16 70 20 73 21 66 29 50 7 50 78 7 51 16 75 69 61 77 3536 4 41 73 14 17 20 4 17 76 23 68 8 6 52 70 55 37 50 44 6 54 16 55 14 5163 70 65 13 25 64 4 74 80 79 45 48 58 34 25 34 52 30 10 16 36 30 65 5441 73 53 8 51 56 30 5 43 69 55 42 14 7 74 47 63 21 74 20 11 8 38 60 7573 40 29 14 44 73 41 9 62 24 25 9 39 6 33 17 66 68 72 74 58 44 68 1 7671 1 70 44 13 74 16 48 50 51 56 53 72 12 70 80 1 4 36 30 44 27 42 50 4579 64 62 79 59 76 77 42 71 17 14 58 31 44 21 56 10 74 54 8


12. The transmit end according to claim 9, wherein the matrix H_(IR) ofQ rows and 24 columns is any Q-row matrix in a preset 100-row matrix,each row in the preset 100-row matrix comprises 24 elements, eachelement represents one square submatrix whose size is Z×Z, a nullelement in each row represents an all-zero matrix, a specific value of anon-null element in each row is a cyclic permutation value of anidentity matrix, and the preset 100-row matrix is as follows: 60 15 3480 20 29 39 22 77 7 7 72 79 69 49 75 8 2 56 22 58 18 47 21 80 38 50 7532 21 26 30 36 44 67 63 2 55 18 63 78 44 67 14 35 73 9 56 5 9 45 67 5025 8 53 45 28 50 62 34 8 4 76 80 50 13 40 32 0 20 47 38 55 45 67 71 5738 47 79 7 76 27 33 49 58 19 26 31 39 68 17 6 76 24 69 3 43 40 34 37 421 10 59 47 66 63 74 26 47 3 53 67 67 46 69 56 35 36 54 17 7 26 77 24 4332 36 9 76 3 78 14 45 0 59 39 4 4 54 31 31 48 39 33 32 34 46 47 6 69 2266 64 10 77 42 23 62 65 43 43 6 48 16 29 23 3 11 44 34 70 59 49 16 1 7719 8 10 17 44 20 18 17 17 71 16 4 69 27 18 36 0 52 43 42 39 56 31 14 509 22 38 64 80 43 80 59 34 48 31 22 77 71 21 54 41 65 58 78 47 56 70 2113 8 41 22 19 63 74 59 58 17 14 59 72 32 29 29 71 79 21 24 46 46 19 5153 75 34 28 79 24 34 64 73 25 49 48 18 64 72 41 41 1 32 74 45 9 50 25 7218 75 11 40 34 43 57 71 76 29 74 67 54 5 23 66 70 41 17 59 72 74 3 25 3154 65 68 15 18 29 11 21 33 30 29 80 50 41 79 51 41 45 18 77 3 51 6 34 5867 14 30 56 69 64 58 59 11 74 48 38 41 52 16 58 63 80 8 2 25 64 35 68 426 39 66 61 26 50 31 11 18 73 80 44 54 28 68 0 55 53 3 42 65 72 73 54 1169 44 15 70 57 48 61 48 30 72 80 47 4 23 72 59 4 69 66 22 52 53 60 35 1365 44 68 16 9 9 10 3 7 50 5 62 20 80


13. A receive end, wherein the receive end comprises: at least oneprocessor; and one or more memories coupled to the at least oneprocessor and storing programming instructions for execution by the atleast one processor to obtain an encoded first codeword and decode theencoded first codeword based on a first check matrix, wherein a codelength of the encoded first codeword is (n+j×Z), and the encoded firstcodeword comprises k information bits and (n−k+j×Z) redundant bits,wherein: the first check matrix is a submatrix of the first ((n−k)/Z+j)rows and the first (n/Z+j) columns in a check matrix H, and a code rateof the first check matrix is equal to a first transmission code rate; nis an integer greater than 0, j is an integer greater than or equal to0, and Z is an integer greater than 0; the check matrix H is a matrix of((n−k)/Z+Q) rows and (n/Z+Q) columns, Q is an integer greater than orequal to j, each element in the check matrix H represents one Z×Z squaresubmatrix, and the square submatrix is a cyclic permutation matrix of anidentity matrix or an all-zero matrix; the check matrix H comprises amatrix HMC, a matrix HIR of Q rows and 24 columns, an all-zero matrix of4 rows and Q columns, and an identity matrix of Q rows and Q columns;and the matrix H_(MC) is a matrix of (n−k)/Z rows and n/Z columns, thematrix HMC is located at an upper left corner of the check matrix H, thematrix H_(IR) of Q rows and 24 columns is located at a lower left cornerof the check matrix H, the all-zero matrix of 4 rows and Q columns islocated at an upper right corner of the check matrix H, and the identitymatrix of Q rows and Q columns is located at a lower right corner of thecheck matrix H.
 14. The receive end according to claim 13, wherein theprogramming instructions are for execution by the at least one processorto: receive incremental redundant bits that are transmitted by atransmit end for a second time or some of the k information bits and theincremental redundant bits that are transmitted by the transmit end;combine the incremental redundant bits to an end of the first codewordto form a second codeword; and decode the second codeword based on asecond check matrix, wherein the second check matrix is a submatrix ofthe first ((n−k)/Z+h) rows and the first (n/Z+h) columns in the checkmatrix H, a code rate of the second check matrix is equal to a secondtransmission code rate, and h is an integer greater than j and less thanor equal to Q.
 15. The receive end according to claim 13, wherein thematrix H_(IR) of Q rows and 24 columns is any Q-row matrix in a preset136-row matrix, each row in the preset 136-row matrix comprises 24elements, each element represents one square submatrix whose size isZ×Z, a null element in each row represents an all-zero matrix, aspecific value of a non-null element in each row is a cyclic permutationvalue of an identity matrix, and the preset 136-row matrix is asfollows: 25 24 6 47 73 23 16 49 30 16 47 19 65 40 44 0 60 71 56 53 55 2455 39 79 68 14 43 71 18 8 25 18 16 73 35 17 53 30 13 57 47 52 5 78 13 3177 13 10 53 23 66 48 71 11 4 66 10 9 10 37 18 52 68 2 43 75 73 12 55 2933 49 0 69 62 55 33 4 51 39 24 33 7 42 80 31 60 52 44 69 41 19 37 10 6128 9 27 49 61 54 30 69 56 18 24 68 39 34 49 47 40 35 43 72 27 45 52 3455 9 33 58 68 77 38 52 51 45 40 40 20 19 71 4 9 62 26 26 61 45 60 21 663 53 79 4 74 19 57 40 16 28 65 37 43 40 52 51 78 79 60 11 40 52 79 4670 51 70 80 20 42 58 6 4 14 31 80 5 20 68 37 32 75 28 74 42 16 75 80 6335 52 14 62 8 29 45 26 57 56 24 40 33 51 17 32 80 2 49 78 12 24 55 34 804 36 24 64 20 56 38 77 50 47 21 34 65 69 17 44 59 63 10 55 58 68 30 69 711 59 25 76 8 39 11 49 67 39 26 57 73 24 45 42 1 60 73 73 56 77 10 3 3961 44 70 68 7 43 78 20 55 76 3 37 59 7 38 70 64 41 63 31 63 2 5 60 78 5710 67 17 17 0 46 59 51 7 33 22 27 4 19 9 6 0 43 38 64 5 63 73 55 7 44 1221 31 28 57 2 28 32 65 45 2 41 53 60 62 67 65 56 17 14 53 1 20 31 34 210 65 63 32 14 39 11 58 18 75 43 74 25 75 0 65 6 80 67 16 58 76 2 76 2 7070 19 5 26 61 46 16 70 20 73 21 66 29 50 7 50 78 7 51 16 75 69 61 77 3536 4 41 73 14 17 20 4 17 76 23 68 8 6 52 70 55 37 50 44 6 54 16 55 14 5163 70 65 13 25 64 4 74 80 79 45 48 58 34 25 34 52 30 10 16 36 30 65 5441 73 53 8 51 56 30 5 43 69 55 42 14 7 74 47 63 21 74 20 11 8 38 60 7573 40 29 14 44 73 41 9 62 24 25 9 39 6 33 17 66 68 72 74 58 44 68 1 7671 1 70 44 13 74 16 48 50 51 56 53 72 12 70 80 1 4 36 30 44 27 42 50 4579 64 62 79 59 76 77 42 71 17 14 58 31 44 21 56 10 74 54 8


16. The receive end according to claim 13, wherein the matrix H_(IR) ofQ rows and 24 columns is any Q-row matrix in a preset 100-row matrix,each row in the preset 100-row matrix comprises 24 elements, eachelement represents one square submatrix whose size is Z×Z, a nullelement in each row represents an all-zero matrix, a specific value of anon-null element in each row is a cyclic permutation value of anidentity matrix, and the preset 100-row matrix is as follows: 60 15 3480 20 29 39 22 77 7 7 72 79 69 49 75 8 2 56 22 58 18 47 21 80 38 50 7532 21 26 30 36 44 67 63 2 55 18 63 78 44 67 14 35 73 9 56 5 9 45 67 5025 8 53 45 28 50 62 34 8 4 76 80 50 13 40 32 0 20 47 38 55 45 67 71 5738 47 79 7 76 27 33 49 58 19 26 31 39 68 17 6 76 24 69 3 43 40 34 37 421 10 59 47 66 63 74 26 47 3 53 67 67 46 69 56 35 36 54 17 7 26 77 24 4332 36 9 76 3 78 14 45 0 59 39 4 4 54 31 31 48 39 33 32 34 46 47 6 69 2266 64 10 77 42 23 62 65 43 43 6 48 16 29 23 3 11 44 34 70 59 49 16 1 7719 8 10 17 44 20 18 17 17 71 16 4 69 27 18 36 0 52 43 42 39 56 31 14 509 22 38 64 80 43 80 59 34 48 31 22 77 71 21 54 41 65 58 78 47 56 70 2113 8 41 22 19 63 74 59 58 17 14 59 72 32 29 29 71 79 21 24 46 46 19 5153 75 34 28 79 24 34 64 73 25 49 48 18 64 72 41 41 1 32 74 45 9 50 25 7218 75 11 40 34 43 57 71 76 29 74 67 54 5 23 66 70 41 17 59 72 74 3 25 3154 65 68 15 18 29 11 21 33 30 29 80 50 41 79 51 41 45 18 77 3 51 6 34 5867 14 30 56 69 64 58 59 11 74 48 38 41 52 16 58 63 80 8 2 25 64 35 68 426 39 66 61 26 50 31 11 18 73 80 44 54 28 68 0 55 53 3 42 65 72 73 54 1169 44 15 70 57 48 61 48 30 72 80 47 4 23 72 59 4 69 66 22 52 53 60 35 1365 44 68 16 9 9 10 3 7 50 5 62 20 80